diff --git a/superset/jinja_context.py b/superset/jinja_context.py
index 56724411b1..47ee5488f1 100644
--- a/superset/jinja_context.py
+++ b/superset/jinja_context.py
@@ -113,8 +113,11 @@ def filter_values(column, default=None):
 
         for f in form_data[filter_type]:
             if f['col'] == column:
-                for v in f['val']:
-                    return_val.append(v)
+                if isinstance(f['val'], list):
+                    for v in f['val']:
+                        return_val.append(v)
+                else:
+                    return_val.append(f['val'])
 
     if return_val:
         return return_val
diff --git a/tests/macro_tests.py b/tests/macro_tests.py
index 75905ca7dd..05cc11ef2e 100644
--- a/tests/macro_tests.py
+++ b/tests/macro_tests.py
@@ -48,9 +48,19 @@ class MacroTestCase(SupersetTestCase):
             ],
         }
 
+        form_data4 = {
+            'extra_filters': [
+                {'col': 'my_special_filter', 'op': 'in', 'val': 'foo'},
+            ],
+            'filters': [
+                {'col': 'my_special_filter', 'op': 'in', 'val': 'savage'},
+            ],
+        }
+
         data1 = {'form_data': json.dumps(form_data1)}
         data2 = {'form_data': json.dumps(form_data2)}
         data3 = {'form_data': json.dumps(form_data3)}
+        data4 = {'form_data': json.dumps(form_data4)}
 
         with app.test_request_context(data=data1):
             filter_values = jinja_context.filter_values('my_special_filter')
@@ -73,3 +83,7 @@ class MacroTestCase(SupersetTestCase):
         with app.test_request_context():
             filter_values = jinja_context.filter_values('nonexistent_filter', 'foo')
             self.assertEqual(filter_values, ['foo'])
+
+        with app.test_request_context(data=data4):
+            filter_values = jinja_context.filter_values('my_special_filter')
+            self.assertEqual(filter_values, ['savage', 'foo'])