diff --git a/frontend_tests/node_tests/composebox_typeahead.js b/frontend_tests/node_tests/composebox_typeahead.js
index 10f95da62c..7d9df5d7de 100644
--- a/frontend_tests/node_tests/composebox_typeahead.js
+++ b/frontend_tests/node_tests/composebox_typeahead.js
@@ -59,6 +59,8 @@ global.people.add({
     assert_typeahead_equals("test @", false);
     assert_typeahead_equals("test no@o", false);
     assert_typeahead_equals("test :-P", false);
+    assert_typeahead_equals("test # a", false);
+    assert_typeahead_equals("test #", false);
 
     var all_items = [
         {
diff --git a/static/js/composebox_typeahead.js b/static/js/composebox_typeahead.js
index 5d248fea87..e041daf193 100644
--- a/static/js/composebox_typeahead.js
+++ b/static/js/composebox_typeahead.js
@@ -289,6 +289,11 @@ exports.compose_content_begins_typeahead = function (query) {
             return false;
         }
 
+        // Don't autocomplete if there is a space following a '#'
+        if (current_token[0] === " ") {
+            return false;
+        }
+
         this.completing = 'stream';
         this.token = current_token.substring(current_token.indexOf("#")+1);
         return stream_data.subscribed_subs();