diff --git a/packages/ember-routing-htmlbars/lib/keywords/render.js b/packages/ember-routing-htmlbars/lib/keywords/render.js
index 9be9782c97f..2e7155b0bbb 100644
--- a/packages/ember-routing-htmlbars/lib/keywords/render.js
+++ b/packages/ember-routing-htmlbars/lib/keywords/render.js
@@ -74,7 +74,10 @@ export default {
     }
 
     // # legacy namespace
+    let originalName = name;
     name = name.replace(/\//g, '.');
+    Ember.deprecate(`Using a slash for namespacing with the {{render}} render helper has been deprecated.
+                     Please replace "${originalName}" with "${name}" in your call to the {{render}} helper.`, !originalName.match(/\//g));
     // \ legacy slash as namespace support
 
     var templateName = 'template:' + name;
diff --git a/packages/ember-routing-htmlbars/tests/helpers/render_test.js b/packages/ember-routing-htmlbars/tests/helpers/render_test.js
index b5a6dc4b051..88578c1535c 100644
--- a/packages/ember-routing-htmlbars/tests/helpers/render_test.js
+++ b/packages/ember-routing-htmlbars/tests/helpers/render_test.js
@@ -552,7 +552,7 @@ QUnit.test('{{render}} works with slash notation', function() {
 
   Ember.TEMPLATES['blog.post'] = compile('{{uniqueId}}');
 
-  runAppend(view);
+  expectDeprecation(() => { runAppend(view); }, /Using a slash for namespacing/);
 
   var singletonController = container.lookup('controller:blog.post');
   equal(singletonController.uniqueId, view.$().html(), 'rendered with correct singleton controller');