diff --git a/python/ray/node.py b/python/ray/node.py
index 100bf7dbe..f1ea737de 100644
--- a/python/ray/node.py
+++ b/python/ray/node.py
@@ -14,6 +14,7 @@ import time
 import ray
 import ray.ray_constants as ray_constants
 import ray.services
+import ray.utils
 from ray.resource_spec import ResourceSpec
 from ray.utils import try_to_create_directory, try_to_symlink
 
@@ -82,7 +83,7 @@ class Node:
         ray_params.update_if_absent(
             include_log_monitor=True,
             resources={},
-            temp_dir="/tmp/ray",
+            temp_dir=ray.utils.get_ray_temp_dir(),
             worker_path=os.path.join(
                 os.path.dirname(os.path.abspath(__file__)),
                 "workers/default_worker.py"))
@@ -313,7 +314,7 @@ class Node:
         """Get the path of the sockets directory."""
         return self._sockets_dir
 
-    def _make_inc_temp(self, suffix="", prefix="", directory_name="/tmp/ray"):
+    def _make_inc_temp(self, suffix="", prefix="", directory_name=None):
         """Return a incremental temporary file name. The file is not created.
 
         Args:
@@ -326,6 +327,8 @@ class Node:
                 the same name, the returned name will look like
                 "{directory_name}/{prefix}.{unique_index}{suffix}"
         """
+        if directory_name is None:
+            directory_name = ray.utils.get_ray_temp_dir()
         directory_name = os.path.expanduser(directory_name)
         index = self._incremental_dict[suffix, prefix, directory_name]
         # `tempfile.TMP_MAX` could be extremely large,
diff --git a/python/ray/projects/scripts.py b/python/ray/projects/scripts.py
index d02649f50..2610f3232 100644
--- a/python/ray/projects/scripts.py
+++ b/python/ray/projects/scripts.py
@@ -199,9 +199,9 @@ class SessionRunner:
             requirements_txt = project_environment["requirements"]
 
             # Create a temporary requirements_txt in the head node.
-            remote_requirements_txt = (
-                "/tmp/" + "ray_project_requirements_txt_{}".format(
-                    time.time()))
+            remote_requirements_txt = os.path.join(
+                ray.utils.get_user_temp_dir(),
+                "ray_project_requirements_txt_{}".format(time.time()))
 
             rsync(
                 self.project_definition.cluster_yaml(),
diff --git a/python/ray/reporter.py b/python/ray/reporter.py
index 23117adff..b78ac1784 100644
--- a/python/ray/reporter.py
+++ b/python/ray/reporter.py
@@ -7,6 +7,7 @@ import time
 import datetime
 import grpc
 import subprocess
+import sys
 from concurrent import futures
 
 import ray
@@ -30,7 +31,7 @@ class ReporterServer(reporter_pb2_grpc.ReporterServiceServicer):
     def GetProfilingStats(self, request, context):
         pid = request.pid
         duration = request.duration
-        profiling_file_path = os.path.join("/tmp/ray/",
+        profiling_file_path = os.path.join(ray.utils.get_ray_temp_dir(),
                                            "{}_profiling.txt".format(pid))
         process = subprocess.Popen(
             "sudo $(which py-spy) record -o {} -p {} -d {} -f speedscope"
@@ -127,7 +128,11 @@ class Reporter:
 
     @staticmethod
     def get_disk_usage():
-        return {x: psutil.disk_usage(x) for x in ["/", "/tmp"]}
+        dirs = [
+            os.environ["USERPROFILE"] if sys.platform == "win32" else os.sep,
+            ray.utils.get_user_temp_dir(),
+        ]
+        return {x: psutil.disk_usage(x) for x in dirs}
 
     @staticmethod
     def get_workers():
diff --git a/python/ray/scripts/scripts.py b/python/ray/scripts/scripts.py
index 09cfddd7e..28b9c3498 100644
--- a/python/ray/scripts/scripts.py
+++ b/python/ray/scripts/scripts.py
@@ -912,7 +912,8 @@ def timeline(address):
     logger.info("Connecting to Ray instance at {}.".format(address))
     ray.init(address=address)
     time = datetime.today().strftime("%Y-%m-%d_%H-%M-%S")
-    filename = "/tmp/ray-timeline-{}.json".format(time)
+    filename = os.path.join(ray.utils.get_user_temp_dir(),
+                            "ray-timeline-{}.json".format(time))
     ray.timeline(filename=filename)
     size = os.path.getsize(filename)
     logger.info("Trace file written to {} ({} bytes).".format(filename, size))
diff --git a/python/ray/services.py b/python/ray/services.py
index 95ee2c484..4a206a00b 100644
--- a/python/ray/services.py
+++ b/python/ray/services.py
@@ -423,8 +423,9 @@ def start_ray_process(command,
                 "If 'use_gdb' is true, then 'use_tmux' must be true as well.")
 
         # TODO(suquark): Any better temp file creation here?
-        gdb_init_path = "/tmp/ray/gdb_init_{}_{}".format(
-            process_type, time.time())
+        gdb_init_path = os.path.join(
+            ray.utils.get_ray_temp_dir(), "gdb_init_{}_{}".format(
+                process_type, time.time()))
         ray_process_path = command[0]
         ray_process_args = command[1:]
         run_args = " ".join(["'{}'".format(arg) for arg in ray_process_args])
@@ -1431,18 +1432,18 @@ def determine_plasma_store_config(object_store_memory,
             if shm_avail > object_store_memory:
                 plasma_directory = "/dev/shm"
             else:
-                plasma_directory = "/tmp"
+                plasma_directory = ray.utils.get_user_temp_dir()
                 logger.warning(
-                    "WARNING: The object store is using /tmp instead of "
+                    "WARNING: The object store is using {} instead of "
                     "/dev/shm because /dev/shm has only {} bytes available. "
                     "This may slow down performance! You may be able to free "
                     "up space by deleting files in /dev/shm or terminating "
                     "any running plasma_store_server processes. If you are "
                     "inside a Docker container, you may need to pass an "
                     "argument with the flag '--shm-size' to 'docker run'.".
-                    format(shm_avail))
+                    format(ray.utils.get_user_temp_dir(), shm_avail))
         else:
-            plasma_directory = "/tmp"
+            plasma_directory = ray.utils.get_user_temp_dir()
 
         # Do some sanity checks.
         if object_store_memory > system_memory:
diff --git a/python/ray/tests/test_actor_failures.py b/python/ray/tests/test_actor_failures.py
index 8da0ba248..f9ef76644 100644
--- a/python/ray/tests/test_actor_failures.py
+++ b/python/ray/tests/test_actor_failures.py
@@ -22,7 +22,8 @@ from ray.test_utils import (relevant_errors, wait_for_condition,
 
 @pytest.fixture
 def ray_checkpointable_actor_cls(request):
-    checkpoint_dir = "/tmp/ray_temp_checkpoint_dir/"
+    checkpoint_dir = os.path.join(ray.utils.get_user_temp_dir(),
+                                  "ray_temp_checkpoint_dir") + os.sep
     if not os.path.isdir(checkpoint_dir):
         os.mkdir(checkpoint_dir)
 
diff --git a/python/ray/tests/test_advanced_3.py b/python/ray/tests/test_advanced_3.py
index 6b693f002..3b4bdd23b 100644
--- a/python/ray/tests/test_advanced_3.py
+++ b/python/ray/tests/test_advanced_3.py
@@ -465,7 +465,8 @@ def test_pandas_parquet_serialization():
 
 def test_socket_dir_not_existing(shutdown_only):
     random_name = ray.ObjectID.from_random().hex()
-    temp_raylet_socket_dir = "/tmp/ray/tests/{}".format(random_name)
+    temp_raylet_socket_dir = os.path.join(ray.utils.get_ray_temp_dir(),
+                                          "tests", random_name)
     temp_raylet_socket_name = os.path.join(temp_raylet_socket_dir,
                                            "raylet_socket")
     ray.init(num_cpus=1, raylet_socket_name=temp_raylet_socket_name)
diff --git a/python/ray/tests/test_projects.py b/python/ray/tests/test_projects.py
index becc778a6..b2d6b60da 100644
--- a/python/ray/tests/test_projects.py
+++ b/python/ray/tests/test_projects.py
@@ -51,7 +51,7 @@ def test_project_root():
     project_definition = ray.projects.ProjectDefinition(path2)
     assert os.path.normpath(project_definition.root) == os.path.normpath(path)
 
-    path3 = "/tmp/"
+    path3 = ray.utils.get_user_temp_dir() + os.sep
     with pytest.raises(ValueError):
         project_definition = ray.projects.ProjectDefinition(path3)
 
diff --git a/python/ray/tests/test_tempfile.py b/python/ray/tests/test_tempfile.py
index 6acd7dc01..473d940a3 100644
--- a/python/ray/tests/test_tempfile.py
+++ b/python/ray/tests/test_tempfile.py
@@ -4,6 +4,7 @@ import time
 import pytest
 import ray
 import ray.ray_constants as ray_constants
+import subprocess
 from ray.cluster_utils import Cluster
 
 
@@ -12,7 +13,8 @@ def test_conn_cluster():
     with pytest.raises(Exception) as exc_info:
         ray.init(
             address="127.0.0.1:6379",
-            plasma_store_socket_name="/tmp/this_should_fail")
+            plasma_store_socket_name=os.path.join(
+                ray.utils.get_user_temp_dir(), "this_should_fail"))
     assert exc_info.value.args[0] == (
         "When connecting to an existing cluster, "
         "plasma_store_socket_name must not be provided.")
@@ -21,74 +23,111 @@ def test_conn_cluster():
     with pytest.raises(Exception) as exc_info:
         ray.init(
             address="127.0.0.1:6379",
-            raylet_socket_name="/tmp/this_should_fail")
+            raylet_socket_name=os.path.join(ray.utils.get_user_temp_dir(),
+                                            "this_should_fail"))
     assert exc_info.value.args[0] == (
         "When connecting to an existing cluster, "
         "raylet_socket_name must not be provided.")
 
     # temp_dir
     with pytest.raises(Exception) as exc_info:
-        ray.init(address="127.0.0.1:6379", temp_dir="/tmp/this_should_fail")
+        ray.init(
+            address="127.0.0.1:6379",
+            temp_dir=os.path.join(ray.utils.get_user_temp_dir(),
+                                  "this_should_fail"))
     assert exc_info.value.args[0] == (
         "When connecting to an existing cluster, "
         "temp_dir must not be provided.")
 
 
 def test_tempdir(shutdown_only):
-    shutil.rmtree("/tmp/ray", ignore_errors=True)
-    ray.init(temp_dir="/tmp/i_am_a_temp_dir")
+    shutil.rmtree(ray.utils.get_ray_temp_dir(), ignore_errors=True)
+    ray.init(
+        temp_dir=os.path.join(ray.utils.get_user_temp_dir(),
+                              "i_am_a_temp_dir"))
     assert os.path.exists(
-        "/tmp/i_am_a_temp_dir"), "Specified temp dir not found."
-    assert not os.path.exists("/tmp/ray"), "Default temp dir should not exist."
-    shutil.rmtree("/tmp/i_am_a_temp_dir", ignore_errors=True)
+        os.path.join(ray.utils.get_user_temp_dir(),
+                     "i_am_a_temp_dir")), "Specified temp dir not found."
+    assert not os.path.exists(
+        ray.utils.get_ray_temp_dir()), ("Default temp dir should not exist.")
+    shutil.rmtree(
+        os.path.join(ray.utils.get_user_temp_dir(), "i_am_a_temp_dir"),
+        ignore_errors=True)
 
 
 def test_tempdir_commandline():
-    shutil.rmtree("/tmp/ray", ignore_errors=True)
-    os.system("ray start --head --temp-dir=/tmp/i_am_a_temp_dir2")
+    shutil.rmtree(ray.utils.get_ray_temp_dir(), ignore_errors=True)
+    subprocess.check_call([
+        "ray", "start", "--head", "--temp-dir=" + os.path.join(
+            ray.utils.get_user_temp_dir(), "i_am_a_temp_dir2")
+    ])
     assert os.path.exists(
-        "/tmp/i_am_a_temp_dir2"), "Specified temp dir not found."
-    assert not os.path.exists("/tmp/ray"), "Default temp dir should not exist."
-    os.system("ray stop")
-    shutil.rmtree("/tmp/i_am_a_temp_dir2", ignore_errors=True)
+        os.path.join(ray.utils.get_user_temp_dir(),
+                     "i_am_a_temp_dir2")), "Specified temp dir not found."
+    assert not os.path.exists(
+        ray.utils.get_ray_temp_dir()), "Default temp dir should not exist."
+    subprocess.check_call(["ray", "stop"])
+    shutil.rmtree(
+        os.path.join(ray.utils.get_user_temp_dir(), "i_am_a_temp_dir2"),
+        ignore_errors=True)
 
 
 def test_raylet_socket_name(shutdown_only):
-    ray.init(raylet_socket_name="/tmp/i_am_a_temp_socket")
+    ray.init(
+        raylet_socket_name=os.path.join(ray.utils.get_user_temp_dir(),
+                                        "i_am_a_temp_socket"))
     assert os.path.exists(
-        "/tmp/i_am_a_temp_socket"), "Specified socket path not found."
+        os.path.join(ray.utils.get_user_temp_dir(),
+                     "i_am_a_temp_socket")), "Specified socket path not found."
     ray.shutdown()
     try:
-        os.remove("/tmp/i_am_a_temp_socket")
+        os.remove(
+            os.path.join(ray.utils.get_user_temp_dir(), "i_am_a_temp_socket"))
     except OSError:
         pass  # It could have been removed by Ray.
     cluster = Cluster(True)
-    cluster.add_node(raylet_socket_name="/tmp/i_am_a_temp_socket_2")
+    cluster.add_node(
+        raylet_socket_name=os.path.join(ray.utils.get_user_temp_dir(),
+                                        "i_am_a_temp_socket_2"))
     assert os.path.exists(
-        "/tmp/i_am_a_temp_socket_2"), "Specified socket path not found."
+        os.path.join(
+            ray.utils.get_user_temp_dir(),
+            "i_am_a_temp_socket_2")), "Specified socket path not found."
     cluster.shutdown()
     try:
-        os.remove("/tmp/i_am_a_temp_socket_2")
+        os.remove(
+            os.path.join(ray.utils.get_user_temp_dir(),
+                         "i_am_a_temp_socket_2"))
     except OSError:
         pass  # It could have been removed by Ray.
 
 
 def test_temp_plasma_store_socket(shutdown_only):
-    ray.init(plasma_store_socket_name="/tmp/i_am_a_temp_socket")
+    ray.init(
+        plasma_store_socket_name=os.path.join(ray.utils.get_user_temp_dir(),
+                                              "i_am_a_temp_socket"))
     assert os.path.exists(
-        "/tmp/i_am_a_temp_socket"), "Specified socket path not found."
+        os.path.join(ray.utils.get_user_temp_dir(),
+                     "i_am_a_temp_socket")), "Specified socket path not found."
     ray.shutdown()
     try:
-        os.remove("/tmp/i_am_a_temp_socket")
+        os.remove(
+            os.path.join(ray.utils.get_user_temp_dir(), "i_am_a_temp_socket"))
     except OSError:
         pass  # It could have been removed by Ray.
     cluster = Cluster(True)
-    cluster.add_node(plasma_store_socket_name="/tmp/i_am_a_temp_socket_2")
+    cluster.add_node(
+        plasma_store_socket_name=os.path.join(ray.utils.get_user_temp_dir(),
+                                              "i_am_a_temp_socket_2"))
     assert os.path.exists(
-        "/tmp/i_am_a_temp_socket_2"), "Specified socket path not found."
+        os.path.join(
+            ray.utils.get_user_temp_dir(),
+            "i_am_a_temp_socket_2")), "Specified socket path not found."
     cluster.shutdown()
     try:
-        os.remove("/tmp/i_am_a_temp_socket_2")
+        os.remove(
+            os.path.join(ray.utils.get_user_temp_dir(),
+                         "i_am_a_temp_socket_2"))
     except OSError:
         pass  # It could have been removed by Ray.
 
@@ -135,7 +174,7 @@ def test_raylet_tempfiles(shutdown_only):
 
 
 def test_tempdir_privilege(shutdown_only):
-    os.chmod("/tmp/ray", 0o000)
+    os.chmod(ray.utils.get_ray_temp_dir(), 0o000)
     ray.init(num_cpus=1)
     session_dir = ray.worker._global_node.get_session_dir_path()
     assert os.path.exists(session_dir), "Specified socket path not found."
diff --git a/python/ray/tune/examples/durable_trainable_example.py b/python/ray/tune/examples/durable_trainable_example.py
index 4e13abf34..97bad8af1 100644
--- a/python/ray/tune/examples/durable_trainable_example.py
+++ b/python/ray/tune/examples/durable_trainable_example.py
@@ -19,9 +19,11 @@ class MockDurableTrainable(DurableTrainable):
     def __init__(self, remote_checkpoint_dir, *args, **kwargs):
         # Mock the path as a local path.
         local_dir_suffix = remote_checkpoint_dir.split("://")[1]
-        remote_checkpoint_dir = os.path.join("/tmp", local_dir_suffix)
+        remote_checkpoint_dir = os.path.join(ray.utils.get_user_temp_dir(),
+                                             local_dir_suffix)
         # Disallow malformed relative paths for delete safety.
-        assert os.path.abspath(remote_checkpoint_dir).startswith("/tmp")
+        assert os.path.abspath(remote_checkpoint_dir).startswith(
+            ray.utils.get_user_temp_dir())
         logger.info("Using %s as the mocked remote checkpoint directory.",
                     self.remote_checkpoint_dir)
         super(MockDurableTrainable, self).__init__(remote_checkpoint_dir,
diff --git a/python/ray/tune/examples/pbt_dcgan_mnist/pbt_dcgan_mnist.py b/python/ray/tune/examples/pbt_dcgan_mnist/pbt_dcgan_mnist.py
index 2515b1eed..fb743898e 100644
--- a/python/ray/tune/examples/pbt_dcgan_mnist/pbt_dcgan_mnist.py
+++ b/python/ray/tune/examples/pbt_dcgan_mnist/pbt_dcgan_mnist.py
@@ -26,7 +26,7 @@ from torch.nn import functional as F
 from scipy.stats import entropy
 
 # Training parameters
-dataroot = "/tmp/"
+dataroot = ray.utils.get_user_temp_dir() + os.sep
 workers = 2
 batch_size = 64
 image_size = 32
diff --git a/python/ray/tune/tests/test_api.py b/python/ray/tune/tests/test_api.py
index c578b26bd..a906022eb 100644
--- a/python/ray/tune/tests/test_api.py
+++ b/python/ray/tune/tests/test_api.py
@@ -294,14 +294,16 @@ class TrainableFunctionApiTest(unittest.TestCase):
 
     def testLogdir(self):
         def train(config, reporter):
-            assert "/tmp/logdir/foo" in os.getcwd(), os.getcwd()
+            assert os.path.join(ray.utils.get_user_temp_dir(), "logdir",
+                                "foo") in os.getcwd(), os.getcwd()
             reporter(timesteps_total=1)
 
         register_trainable("f1", train)
         run_experiments({
             "foo": {
                 "run": "f1",
-                "local_dir": "/tmp/logdir",
+                "local_dir": os.path.join(ray.utils.get_user_temp_dir(),
+                                          "logdir"),
                 "config": {
                     "a": "b"
                 },
@@ -330,14 +332,16 @@ class TrainableFunctionApiTest(unittest.TestCase):
 
     def testLongFilename(self):
         def train(config, reporter):
-            assert "/tmp/logdir/foo" in os.getcwd(), os.getcwd()
+            assert os.path.join(ray.utils.get_user_temp_dir(), "logdir",
+                                "foo") in os.getcwd(), os.getcwd()
             reporter(timesteps_total=1)
 
         register_trainable("f1", train)
         run_experiments({
             "foo": {
                 "run": "f1",
-                "local_dir": "/tmp/logdir",
+                "local_dir": os.path.join(ray.utils.get_user_temp_dir(),
+                                          "logdir"),
                 "config": {
                     "a" * 50: tune.sample_from(lambda spec: 5.0 / 7),
                     "b" * 50: tune.sample_from(lambda spec: "long" * 40),
diff --git a/python/ray/tune/tests/test_trainable_util.py b/python/ray/tune/tests/test_trainable_util.py
index 2664b4554..b88948afa 100644
--- a/python/ray/tune/tests/test_trainable_util.py
+++ b/python/ray/tune/tests/test_trainable_util.py
@@ -3,12 +3,15 @@ import pickle
 import shutil
 import unittest
 
+import ray.utils
+
 from ray.tune.trainable import TrainableUtil
 
 
 class TrainableUtilTest(unittest.TestCase):
     def setUp(self):
-        self.checkpoint_dir = "/tmp/tune/MyTrainable123"
+        self.checkpoint_dir = os.path.join(ray.utils.get_user_temp_dir(),
+                                           "tune", "MyTrainable123")
         TrainableUtil.make_checkpoint_dir(self.checkpoint_dir)
 
     def tearDown(self):
diff --git a/python/ray/tune/utils/mock.py b/python/ray/tune/utils/mock.py
index 857de431a..214b05726 100644
--- a/python/ray/tune/utils/mock.py
+++ b/python/ray/tune/utils/mock.py
@@ -1,11 +1,14 @@
 import os
 
+import ray.utils
+
 from ray.rllib.agents.mock import _MockTrainer
 from ray.tune import DurableTrainable
 from ray.tune.sync_client import get_sync_client
 from ray.tune.syncer import NodeSyncer
 
-MOCK_REMOTE_DIR = "/tmp/mock-tune-remote/"
+MOCK_REMOTE_DIR = os.path.join(ray.utils.get_user_temp_dir(),
+                               "mock-tune-remote") + os.sep
 # Sync and delete templates that operate on local directories.
 LOCAL_SYNC_TEMPLATE = "mkdir -p {target} && rsync -avz {source}/ {target}/"
 LOCAL_DELETE_TEMPLATE = "rm -rf {target}"
diff --git a/python/ray/utils.py b/python/ray/utils.py
index b03516abd..f796fce51 100644
--- a/python/ray/utils.py
+++ b/python/ray/utils.py
@@ -8,6 +8,7 @@ import os
 import six
 import subprocess
 import sys
+import tempfile
 import threading
 import time
 import uuid
@@ -29,6 +30,20 @@ win32_job = None
 win32_AssignProcessToJobObject = None
 
 
+def get_user_temp_dir():
+    if sys.platform.startswith("darwin") or sys.platform.startswith("linux"):
+        # Ideally we wouldn't need this fallback, but keep it for now for
+        # for compatibility
+        tempdir = os.path.join(os.sep, "tmp")
+    else:
+        tempdir = tempfile.gettempdir()
+    return tempdir
+
+
+def get_ray_temp_dir():
+    return os.path.join(get_user_temp_dir(), "ray")
+
+
 def _random_string():
     id_hash = hashlib.sha1()
     id_hash.update(uuid.uuid4().bytes)
diff --git a/rllib/examples/export/cartpole_dqn_export.py b/rllib/examples/export/cartpole_dqn_export.py
index adaaf2bea..d500644e0 100644
--- a/rllib/examples/export/cartpole_dqn_export.py
+++ b/rllib/examples/export/cartpole_dqn_export.py
@@ -54,8 +54,8 @@ def restore_checkpoint(export_dir, prefix):
 
 if __name__ == "__main__":
     algo = "DQN"
-    model_dir = "/tmp/model_export_dir"
-    ckpt_dir = "/tmp/ckpt_export_dir"
+    model_dir = os.path.join(ray.utils.get_user_temp_dir(), "model_export_dir")
+    ckpt_dir = os.path.join(ray.utils.get_user_temp_dir(), "ckpt_export_dir")
     prefix = "model.ckpt"
     num_steps = 3
     train_and_export(algo, num_steps, model_dir, ckpt_dir, prefix)
diff --git a/rllib/examples/saving_experiences.py b/rllib/examples/saving_experiences.py
index 6ad53570d..544127b89 100644
--- a/rllib/examples/saving_experiences.py
+++ b/rllib/examples/saving_experiences.py
@@ -3,6 +3,9 @@
 # __sphinx_doc_begin__
 import gym
 import numpy as np
+import os
+
+import ray.utils
 
 from ray.rllib.models.preprocessors import get_preprocessor
 from ray.rllib.evaluation.sample_batch_builder import SampleBatchBuilder
@@ -10,7 +13,8 @@ from ray.rllib.offline.json_writer import JsonWriter
 
 if __name__ == "__main__":
     batch_builder = SampleBatchBuilder()  # or MultiAgentSampleBatchBuilder
-    writer = JsonWriter("/tmp/demo-out")
+    writer = JsonWriter(
+        os.path.join(ray.utils.get_user_temp_dir(), "demo-out"))
 
     # You normally wouldn't want to manually create sample batches if a
     # simulator is available, but let's do it anyways for example purposes:
diff --git a/rllib/tests/test_checkpoint_restore.py b/rllib/tests/test_checkpoint_restore.py
index c6f38ed6b..99d8a6286 100644
--- a/rllib/tests/test_checkpoint_restore.py
+++ b/rllib/tests/test_checkpoint_restore.py
@@ -125,7 +125,8 @@ def export_test(alg_name, failures):
         res = algo.train()
         print("current status: " + str(res))
 
-    export_dir = "/tmp/export_dir_%s" % alg_name
+    export_dir = os.path.join(ray.utils.get_user_temp_dir(),
+                              "export_dir_%s" % alg_name)
     print("Exporting model ", alg_name, export_dir)
     algo.export_policy_model(export_dir)
     if not valid_tf_model(export_dir):
diff --git a/src/ray/common/status.cc b/src/ray/common/status.cc
index 40657d394..e3e954546 100644
--- a/src/ray/common/status.cc
+++ b/src/ray/common/status.cc
@@ -27,11 +27,11 @@
 // Adapted from Apache Arrow, Apache Kudu, TensorFlow
 
 #include "ray/common/status.h"
-#include <map>
 
 #include <assert.h>
 
 #include <boost/system/error_code.hpp>
+#include <map>
 
 namespace ray {
 
diff --git a/src/ray/core_worker/test/core_worker_test.cc b/src/ray/core_worker/test/core_worker_test.cc
index c4bdc80ef..ab769508d 100644
--- a/src/ray/core_worker/test/core_worker_test.cc
+++ b/src/ray/core_worker/test/core_worker_test.cc
@@ -32,6 +32,7 @@
 #include "ray/core_worker/store_provider/memory_store/memory_store.h"
 #include "ray/core_worker/transport/direct_actor_transport.h"
 #include "ray/raylet/raylet_client.h"
+#include "ray/util/filesystem.h"
 #include "src/ray/protobuf/core_worker.pb.h"
 #include "src/ray/protobuf/gcs.pb.h"
 
@@ -149,7 +150,8 @@ class CoreWorkerTest : public ::testing::Test {
   }
 
   std::string StartStore() {
-    std::string store_socket_name = "/tmp/store" + ObjectID::FromRandom().Hex();
+    std::string store_socket_name =
+        ray::JoinPaths(ray::GetUserTempDir(), "store" + ObjectID::FromRandom().Hex());
     std::string store_pid = store_socket_name + ".pid";
     std::string plasma_command = store_executable + " -m 10000000 -s " +
                                  store_socket_name +
@@ -171,7 +173,8 @@ class CoreWorkerTest : public ::testing::Test {
 
   std::string StartRaylet(std::string store_socket_name, std::string node_ip_address,
                           int port, std::string redis_address, std::string resource) {
-    std::string raylet_socket_name = "/tmp/raylet" + ObjectID::FromRandom().Hex();
+    std::string raylet_socket_name =
+        ray::JoinPaths(ray::GetUserTempDir(), "raylet" + ObjectID::FromRandom().Hex());
     std::string ray_start_cmd = raylet_executable;
     ray_start_cmd.append(" --raylet_socket_name=" + raylet_socket_name)
         .append(" --store_socket_name=" + store_socket_name)
@@ -204,8 +207,8 @@ class CoreWorkerTest : public ::testing::Test {
   }
 
   std::string StartRayletMonitor(std::string redis_address) {
-    std::string raylet_monitor_pid =
-        "/tmp/raylet_monitor" + ObjectID::FromRandom().Hex() + ".pid";
+    std::string raylet_monitor_pid = ray::JoinPaths(
+        ray::GetUserTempDir(), "raylet_monitor" + ObjectID::FromRandom().Hex() + ".pid");
     std::string raylet_monitor_start_cmd = raylet_monitor_executable;
     raylet_monitor_start_cmd.append(" --redis_address=" + redis_address)
         .append(" --redis_port=6379")
@@ -225,8 +228,8 @@ class CoreWorkerTest : public ::testing::Test {
   }
 
   std::string StartGcsServer(std::string redis_address) {
-    std::string gcs_server_pid =
-        "/tmp/gcs_server" + ObjectID::FromRandom().Hex() + ".pid";
+    std::string gcs_server_pid = ray::JoinPaths(
+        ray::GetUserTempDir(), "gcs_server" + ObjectID::FromRandom().Hex() + ".pid");
     std::string gcs_server_start_cmd = gcs_server_executable;
     gcs_server_start_cmd.append(" --redis_address=" + redis_address)
         .append(" --redis_port=6379")
diff --git a/src/ray/object_manager/test/object_manager_stress_test.cc b/src/ray/object_manager/test/object_manager_stress_test.cc
index 1f0f52be9..8db2aa7d4 100644
--- a/src/ray/object_manager/test/object_manager_stress_test.cc
+++ b/src/ray/object_manager/test/object_manager_stress_test.cc
@@ -20,10 +20,9 @@
 #include <thread>
 
 #include "gtest/gtest.h"
-
 #include "ray/common/status.h"
-
 #include "ray/object_manager/object_manager.h"
+#include "ray/util/filesystem.h"
 
 namespace ray {
 
@@ -89,7 +88,7 @@ class TestObjectManagerBase : public ::testing::Test {
   }
 
   std::string StartStore(const std::string &id) {
-    std::string store_id = "/tmp/store";
+    std::string store_id = ray::JoinPaths(ray::GetUserTempDir(), "store");
     store_id = store_id + id;
     std::string store_pid = store_id + ".pid";
     std::string plasma_command = store_executable + " -m 1000000000 -s " + store_id +
diff --git a/src/ray/object_manager/test/object_manager_test.cc b/src/ray/object_manager/test/object_manager_test.cc
index a8f5f569e..3b3b7c578 100644
--- a/src/ray/object_manager/test/object_manager_test.cc
+++ b/src/ray/object_manager/test/object_manager_test.cc
@@ -12,16 +12,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include "ray/object_manager/object_manager.h"
+
 #include <unistd.h>
 
 #include <iostream>
 #include <thread>
 
 #include "gtest/gtest.h"
-
 #include "ray/common/status.h"
-
-#include "ray/object_manager/object_manager.h"
+#include "ray/util/filesystem.h"
 
 namespace {
 std::string store_executable;
@@ -83,7 +83,7 @@ class TestObjectManagerBase : public ::testing::Test {
   }
 
   std::string StartStore(const std::string &id) {
-    std::string store_id = "/tmp/store";
+    std::string store_id = ray::JoinPaths(ray::GetUserTempDir(), "store");
     store_id = store_id + id;
     std::string store_pid = store_id + ".pid";
     std::string plasma_command = store_executable + " -m 1000000000 -s " + store_id +
diff --git a/src/ray/raylet/object_manager_integration_test.cc b/src/ray/raylet/object_manager_integration_test.cc
index 4fbace333..e839c9e81 100644
--- a/src/ray/raylet/object_manager_integration_test.cc
+++ b/src/ray/raylet/object_manager_integration_test.cc
@@ -16,10 +16,9 @@
 #include <thread>
 
 #include "gtest/gtest.h"
-
 #include "ray/common/status.h"
-
 #include "ray/raylet/raylet.h"
+#include "ray/util/filesystem.h"
 
 namespace ray {
 
@@ -39,7 +38,7 @@ class TestObjectManagerBase : public ::testing::Test {
   }
 
   std::string StartStore(const std::string &id) {
-    std::string store_id = "/tmp/store";
+    std::string store_id = ray::JoinPaths(ray::GetUserTempDir(), "store");
     store_id = store_id + id;
     std::string plasma_command = store_executable + " -m 1000000000 -s " + store_id +
                                  " 1> /dev/null 2> /dev/null &";
diff --git a/src/ray/util/filesystem.cc b/src/ray/util/filesystem.cc
new file mode 100644
index 000000000..55f1fcd33
--- /dev/null
+++ b/src/ray/util/filesystem.cc
@@ -0,0 +1,47 @@
+#include "ray/util/filesystem.h"
+
+#include <stdlib.h>
+
+#include "ray/util/logging.h"
+
+#ifdef _WIN32
+#include <Windows.h>
+#endif
+
+namespace ray {
+
+std::string GetRayTempDir() { return JoinPaths(GetUserTempDir(), "ray"); }
+
+std::string GetUserTempDir() {
+  std::string result;
+#if defined(__APPLE__) || defined(__linux__)
+  // Prefer the hard-coded path for now, for compatibility.
+  result = "/tmp";
+#elif defined(_WIN32)
+  result.resize(1 << 8);
+  DWORD n = GetTempPath(static_cast<DWORD>(result.size()), &*result.begin());
+  if (n > result.size()) {
+    result.resize(n);
+    n = GetTempPath(static_cast<DWORD>(result.size()), &*result.begin());
+  }
+  result.resize(0 < n && n <= result.size() ? static_cast<size_t>(n) : 0);
+#else  // not Linux, Darwin, or Windows
+  const char *candidates[] = {"TMPDIR", "TMP", "TEMP", "TEMPDIR"};
+  const char *found = NULL;
+  for (char const *candidate : candidates) {
+    found = getenv(candidate);
+    if (found) {
+      break;
+    }
+  }
+  result = found ? found : "/tmp";
+#endif
+  // Strip trailing separators
+  while (!result.empty() && IsDirSep(result.back())) {
+    result.pop_back();
+  }
+  RAY_CHECK(!result.empty());
+  return result;
+}
+
+}  // namespace ray
diff --git a/src/ray/util/filesystem.h b/src/ray/util/filesystem.h
new file mode 100644
index 000000000..c3a8e4abb
--- /dev/null
+++ b/src/ray/util/filesystem.h
@@ -0,0 +1,67 @@
+#ifndef RAY_UTIL_FILESYSTEM_H
+#define RAY_UTIL_FILESYSTEM_H
+
+#include <string>
+
+namespace ray {
+
+/// \return The portable directory separator (slash on all OSes).
+static char GetAltDirSep() { return '/'; }
+
+/// \return The platform directory separator (backslash on Windows, slash on other OSes).
+static char GetDirSep() {
+  char result;
+#ifdef _WIN32
+  result = '\\';
+#else
+  result = '/';
+#endif
+  return result;
+}
+
+/// \return The platform PATH separator (semicolon on Windows, colon on other OSes).
+static char GetPathSep() {
+  char result;
+#ifdef _WIN32
+  result = ';';
+#else
+  result = ':';
+#endif
+  return result;
+}
+
+/// \return A non-volatile temporary directory in which Ray can stores its files.
+std::string GetRayTempDir();
+
+/// \return The non-volatile temporary directory for the current user (often /tmp).
+std::string GetUserTempDir();
+
+/// \return Whether or not the given character is a directory separator on this platform.
+static bool IsDirSep(char ch) {
+  bool result = ch == GetDirSep();
+#ifdef _WIN32
+  result |= ch == GetAltDirSep();
+#endif
+  return result;
+}
+
+/// \return Whether or not the given character is a PATH separator on this platform.
+static bool IsPathSep(char ch) { return ch == GetPathSep(); }
+
+/// \return The result of joining multiple path components.
+template <class... Paths>
+std::string JoinPaths(std::string base, Paths... components) {
+  std::string to_append[] = {components...};
+  for (size_t i = 0; i < sizeof(to_append) / sizeof(*to_append); ++i) {
+    const std::string &s = to_append[i];
+    if (!base.empty() && !IsDirSep(base.back()) && !s.empty() && !IsDirSep(s[0])) {
+      base += GetDirSep();
+    }
+    base += s;
+  }
+  return base;
+}
+
+}  // namespace ray
+
+#endif  // RAY_UTIL_UTIL_H
diff --git a/src/ray/util/logging_test.cc b/src/ray/util/logging_test.cc
index 6fe20f240..340740fda 100644
--- a/src/ray/util/logging_test.cc
+++ b/src/ray/util/logging_test.cc
@@ -12,12 +12,14 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include "ray/util/logging.h"
+
 #include <chrono>
 #include <cstdlib>
 #include <iostream>
 
 #include "gtest/gtest.h"
-#include "ray/util/logging.h"
+#include "ray/util/filesystem.h"
 
 namespace ray {
 
@@ -55,14 +57,15 @@ TEST(PrintLogTest, LogTestWithoutInit) {
 
 TEST(PrintLogTest, LogTestWithInit) {
   // Test empty app name.
-  RayLog::StartRayLog("", RayLogLevel::DEBUG, "/tmp/");
+  RayLog::StartRayLog("", RayLogLevel::DEBUG, ray::GetUserTempDir() + ray::GetDirSep());
   PrintLog();
   RayLog::ShutDownRayLog();
 }
 
 // This test will output large amount of logs to stderr, should be disabled in travis.
 TEST(LogPerfTest, PerfTest) {
-  RayLog::StartRayLog("/fake/path/to/appdire/LogPerfTest", RayLogLevel::ERROR, "/tmp/");
+  RayLog::StartRayLog("/fake/path/to/appdire/LogPerfTest", RayLogLevel::ERROR,
+                      ray::GetUserTempDir() + ray::GetDirSep());
   int rounds = 100000;
 
   int64_t start_time = current_time_ms();
diff --git a/streaming/src/test/queue_tests_base.h b/streaming/src/test/queue_tests_base.h
index 6932b5bf7..e0839ccd7 100644
--- a/streaming/src/test/queue_tests_base.h
+++ b/streaming/src/test/queue_tests_base.h
@@ -1,3 +1,5 @@
+#include "ray/util/filesystem.h"
+
 namespace ray {
 namespace streaming {
 
@@ -70,7 +72,9 @@ class StreamingQueueTestBase : public ::testing::TestWithParam<uint64_t> {
   }
 
   std::string StartStore() {
-    std::string store_socket_name = "/tmp/store" + RandomObjectID().Hex();
+    std::string store_socket_name = ray::JoinPaths(
+        ray::GetUserTempDir(),
+        "store" + RandomObjectID().Hex());
     std::string store_pid = store_socket_name + ".pid";
     std::string plasma_command = store_executable_ + " -m 10000000 -s " +
                                  store_socket_name +
@@ -91,7 +95,9 @@ class StreamingQueueTestBase : public ::testing::TestWithParam<uint64_t> {
   }
 
   std::string StartGcsServer(std::string redis_address) {
-    std::string gcs_server_socket_name = "/tmp/gcs_server" + ObjectID::FromRandom().Hex();
+    std::string gcs_server_socket_name = ray::JoinPaths(
+        ray::GetUserTempDir(),
+        "gcs_server" + ObjectID::FromRandom().Hex());
     std::string ray_start_cmd = gcs_server_executable_;
     ray_start_cmd.append(" --redis_address=" + redis_address)
         .append(" --redis_port=6379")
@@ -116,7 +122,9 @@ class StreamingQueueTestBase : public ::testing::TestWithParam<uint64_t> {
 
   std::string StartRaylet(std::string store_socket_name, std::string node_ip_address,
                           int port, std::string redis_address, std::string resource) {
-    std::string raylet_socket_name = "/tmp/raylet" + RandomObjectID().Hex();
+    std::string raylet_socket_name = ray::JoinPaths(
+        ray::GetUserTempDir(),
+        "raylet" + RandomObjectID().Hex());
     std::string ray_start_cmd = raylet_executable_;
     ray_start_cmd.append(" --raylet_socket_name=" + raylet_socket_name)
         .append(" --store_socket_name=" + store_socket_name)