diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6c07b43e92..5917146aef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## Unreleased - 2019-01-07
+## Fixed
+- Fix typo in some exception names [#522](https://github.com/plotly/dash/pull/522)
+
 ## 0.35.1 - 2018-12-27
 ### Fixed
 - Always skip `dynamic` resources from index resources collection. [#518](https://github.com/plotly/dash/pull/518)
diff --git a/dash/dash.py b/dash/dash.py
index b13ee0f050..21f5e710b7 100644
--- a/dash/dash.py
+++ b/dash/dash.py
@@ -665,7 +665,7 @@ def _validate_callback(self, output, inputs, state, events):
                                           'supress_callback_exceptions') and
                         arg.component_id not in layout and
                         arg.component_id != getattr(layout, 'id', None)):
-                    raise exceptions.NonExistantIdException('''
+                    raise exceptions.NonExistentIdException('''
                         Attempting to assign a callback to the
                         component with the id "{}" but no
                         components with id "{}" exist in the
@@ -698,7 +698,7 @@ def _validate_callback(self, output, inputs, state, events):
                             component.available_properties and not
                             any(arg.component_property.startswith(w) for w in
                                 component.available_wildcard_properties)):
-                        raise exceptions.NonExistantPropException('''
+                        raise exceptions.NonExistentPropException('''
                             Attempting to assign a callback with
                             the property "{}" but the component
                             "{}" doesn't have "{}" as a property.\n
@@ -715,7 +715,7 @@ def _validate_callback(self, output, inputs, state, events):
                     if (hasattr(arg, 'component_event') and
                             arg.component_event not in
                             component.available_events):
-                        raise exceptions.NonExistantEventException('''
+                        raise exceptions.NonExistentEventException('''
                             Attempting to assign a callback with
                             the event "{}" but the component
                             "{}" doesn't have "{}" as an event.\n
diff --git a/dash/exceptions.py b/dash/exceptions.py
index 5d90704a0e..13b4feb044 100644
--- a/dash/exceptions.py
+++ b/dash/exceptions.py
@@ -10,15 +10,15 @@ class CallbackException(DashException):
     pass
 
 
-class NonExistantIdException(CallbackException):
+class NonExistentIdException(CallbackException):
     pass
 
 
-class NonExistantPropException(CallbackException):
+class NonExistentPropException(CallbackException):
     pass
 
 
-class NonExistantEventException(CallbackException):
+class NonExistentEventException(CallbackException):
     pass
 
 
diff --git a/tests/test_react.py b/tests/test_react.py
index e14c62e233..28cc3e9dfe 100644
--- a/tests/test_react.py
+++ b/tests/test_react.py
@@ -381,7 +381,7 @@ def test_exception_id_not_in_layout(self):
         app = dash.Dash('')
         app.layout = Div('', id='test')
         self.assertRaises(
-            exceptions.NonExistantIdException,
+            exceptions.NonExistentIdException,
             app.callback,
             Output('output', 'children'),
             [Input('input', 'value')]
@@ -395,21 +395,21 @@ def test_exception_prop_not_in_component(self):
         ], id='body')
 
         self.assertRaises(
-            exceptions.NonExistantPropException,
+            exceptions.NonExistentPropException,
             app.callback,
             Output('output', 'non-there'),
             [Input('input', 'value')]
         )
 
         self.assertRaises(
-            exceptions.NonExistantPropException,
+            exceptions.NonExistentPropException,
             app.callback,
             Output('output', 'children'),
             [Input('input', 'valuez')]
         )
 
         self.assertRaises(
-            exceptions.NonExistantPropException,
+            exceptions.NonExistentPropException,
             app.callback,
             Output('body', 'childrenz'),
             [Input('input', 'value')]
@@ -426,7 +426,7 @@ def test_exception_event_not_in_component(self):
 
         for id in ['output', 'body']:
             self.assertRaises(
-                exceptions.NonExistantEventException,
+                exceptions.NonExistentEventException,
                 app.callback,
                 Output(id, 'children'),
                 events=[Event(id, 'style')]
@@ -437,7 +437,7 @@ def test_exception_event_not_in_component(self):
             )
 
         self.assertRaises(
-            exceptions.NonExistantEventException,
+            exceptions.NonExistentEventException,
             app.callback,
             Output('output', 'children'),
             events=[Event('graph', 'zoom')]
@@ -474,7 +474,7 @@ def test_suppress_callback_exception(self):
             Div(id='output')
         ], id='body')
         self.assertRaises(
-            exceptions.NonExistantIdException,
+            exceptions.NonExistentIdException,
             app.callback,
             Output('id-not-there', 'children'),
             [Input('input', 'value')]