diff --git a/client/coral-framework/translations.json b/client/coral-framework/translations.json
index 112f7db1a..5bf9b40a9 100644
--- a/client/coral-framework/translations.json
+++ b/client/coral-framework/translations.json
@@ -14,6 +14,8 @@
       "PASSWORD_REQUIRED": "Must input a password",
       "PASSWORD_LENGTH": "Password is too short",
       "EMAIL_IN_USE": "Email address already in use",
+      "EMAIL_DISPLAY_NAME_IN_USE": "Email address or display name already in use",
+      "DISPLAYNAME_IN_USE": "Display name already in use",
       "DISPLAY_NAME_REQUIRED": "Must input a display name",
       "NO_SPECIAL_CHARACTERS": "Display names can contain letters, numbers and _ only",
       "PROFANITY_ERROR": "Display names must not contain profanity. Please contact the administrator if you believe this to be in error."
@@ -34,6 +36,8 @@
       "PASSWORD_REQUIRED": "Debe ingresar una contraseña",
       "PASSWORD_LENGTH": "La contraseña es muy corta",
       "EMAIL_IN_USE": "La dirección de correo electrónico se encuentra en uso",
+      "EMAIL_DISPLAY_NAME_IN_USE": "Correo o Nombre en uso.",
+      "DISPLAYNAME_IN_USE": "Nombre en uso.",
       "DISPLAY_NAME_REQUIRED": "Debe ingresar un nombre",
       "NO_SPECIAL_CHARACTERS": "Los nombres pueden contener letras, números y _",
       "PROFANITY_ERROR": "Los nombres no pueden contener blasfemias. Por favor contacte al administrador si cree que esto es un error"
diff --git a/client/coral-sign-in/translations.js b/client/coral-sign-in/translations.js
index 9155a6789..d4f5208bd 100644
--- a/client/coral-sign-in/translations.js
+++ b/client/coral-sign-in/translations.js
@@ -19,6 +19,7 @@ export default {
       alreadyHaveAnAccount: 'Already have an account?',
       recoverPassword: 'Recover password',
       emailInUse: 'Email address already in use',
+      emailORusernameInUse: 'Email address or Username already in use',
       requiredField: 'This field is required',
       passwordsDontMatch: 'Passwords don\'t match.',
       specialCharacters: 'Display names can contain letters, numbers and _ only',
@@ -45,6 +46,7 @@ export default {
       alreadyHaveAnAccount: 'Ya tienes una cuenta?',
       recoverPassword: 'Recuperar contraseña',
       emailInUse: 'Este email se encuentra en uso',
+      emailORusernameInUse: 'Este email ó nombre se encuentran en uso',
       requiredField: 'Este campo es requerido',
       passwordsDontMatch: 'Las contraseñas no coinciden',
       specialCharacters: 'Los nombres pueden contener letras, números y _',
diff --git a/errors.js b/errors.js
index b5b217b61..1b26e7170 100644
--- a/errors.js
+++ b/errors.js
@@ -54,6 +54,11 @@ const ErrEmailTaken = new APIError('Email address already in use', {
   status: 400
 });
 
+const ErrDisplayTaken = new APIError('Display name already in use', {
+  translation_key: 'DISPLAYNAME_IN_USE',
+  status: 400
+});
+
 const ErrSpecialChars = new APIError('No special characters are allowed in a display name', {
   translation_key: 'NO_SPECIAL_CHARACTERS',
   status: 400
@@ -116,6 +121,7 @@ module.exports = {
   ErrSpecialChars,
   ErrMissingDisplay,
   ErrContainsProfanity,
+  ErrDisplayTaken,
   ErrAssetCommentingClosed,
   ErrNotFound,
   ErrInvalidAssetURL,
diff --git a/models/user.js b/models/user.js
index a0993c55a..a0ca34d7a 100644
--- a/models/user.js
+++ b/models/user.js
@@ -81,7 +81,11 @@ const UserSchema = new mongoose.Schema({
 
   // This is sourced from the social provider or set manually during user setup
   // and simply provides a name to display for the given user.
-  displayName: String,
+  displayName: {
+    type: String,
+    unique: true,
+    required: true
+  },
 
   // This is true when the user account is disabled, no action should be
   // acknowledged when they are disabled. Logins are also prevented.
@@ -379,6 +383,9 @@ UserService.createLocalUser = (email, password, displayName) => {
           user.save((err) => {
             if (err) {
               if (err.code === 11000) {
+                if (err.message.match('displayName')) {
+                  return reject(errors.ErrDisplayTaken);
+                }
                 return reject(errors.ErrEmailTaken);
               }
               return reject(err);
diff --git a/tests/models/user.js b/tests/models/user.js
index 69be314c4..16ccacede 100644
--- a/tests/models/user.js
+++ b/tests/models/user.js
@@ -85,6 +85,22 @@ describe('models.User', () => {
 
   });
 
+  describe('#createLocalUser', () => {
+    it('should not create a user with duplicate display name', () => {
+      return User.createLocalUsers([{
+        email: 'otrostampi@gmail.com',
+        displayName: 'Stampi',
+        password: '1Coralito!'
+      }])
+      .then((user) => {
+        expect(user).to.be.null;
+      })
+      .catch((error) => {
+        expect(error).to.not.be.null;
+      });
+    });
+  });
+
   describe('#createEmailConfirmToken', () => {
 
     it('should create a token for a valid user', () => {