diff --git a/wagtail/wagtailadmin/edit_handlers.py b/wagtail/wagtailadmin/edit_handlers.py
index 1c5ec6a09..137bb207a 100644
--- a/wagtail/wagtailadmin/edit_handlers.py
+++ b/wagtail/wagtailadmin/edit_handlers.py
@@ -485,7 +485,7 @@ class BasePageChooserPanel(BaseChooserPanel):
             if cls.page_type:
                 try:
                     model = resolve_model_string(cls.page_type)
-                except NameError:
+                except LookupError:
                     raise ImproperlyConfigured("{0}.page_type must be of the form 'app_label.model_name', given {1!r}".format(
                         cls.__name__, cls.page_type))
                 except ValueError:
diff --git a/wagtail/wagtailcore/models.py b/wagtail/wagtailcore/models.py
index 6b13c61de..2c5bcaa15 100644
--- a/wagtail/wagtailcore/models.py
+++ b/wagtail/wagtailcore/models.py
@@ -517,7 +517,7 @@ class Page(six.with_metaclass(PageBase, MP_Node, ClusterableModel, index.Indexed
                 try:
                     models = [resolve_model_string(model_string, cls._meta.app_label)
                               for model_string in subpage_types]
-                except NameError as err:
+                except LookupError as err:
                     raise ImproperlyConfigured("{0}.subpage_types must be a list of 'app_label.model_name' strings, given {1!r}".format(
                         cls.__name__, err.args[1]))
                 res = list(map(ContentType.objects.get_for_model, models))
@@ -541,7 +541,7 @@ class Page(six.with_metaclass(PageBase, MP_Node, ClusterableModel, index.Indexed
                 try:
                     models = [resolve_model_string(model_string, cls._meta.app_label)
                               for model_string in parent_page_types]
-                except NameError as err:
+                except LookupError as err:
                     raise ImproperlyConfigured("{0}.parent_page_types must be a list of 'app_label.model_name' strings, given {1!r}".format(
                         cls.__name__, err.args[1]))
                 res = list(map(ContentType.objects.get_for_model, models))
diff --git a/wagtail/wagtailcore/utils.py b/wagtail/wagtailcore/utils.py
index d03d5ae75..403c79bf3 100644
--- a/wagtail/wagtailcore/utils.py
+++ b/wagtail/wagtailcore/utils.py
@@ -28,11 +28,11 @@ def resolve_model_string(model_string, default_app=None):
 
         model = get_model(app_label, model_name)
         if not model:
-            raise NameError("Can not resolve {0!r} in to a model".format(model_string), model_string)
+            raise LookupError("Can not resolve {0!r} in to a model".format(model_string), model_string)
         return model
 
     elif model_string is not None and issubclass(model_string, Model):
         return model
 
     else:
-        raise NameError("Can not resolve {0!r} in to a model".format(model_string), model_string)
+        raise LookupError("Can not resolve {0!r} in to a model".format(model_string), model_string)