diff --git a/README.md b/README.md
index 0e5f9a8a7..d340b0d39 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,7 @@
 # Ray
 
-Ray is a distributed execution framework with a Python-like programming model.
+Ray is an experimental distributed execution framework with a Python-like
+programming model. It is under development and not ready for general use.
 
 ## Design Decisions