diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 88b1ba4e..32434344 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -11,6 +11,7 @@ Current
 - Fix `@api.expect(..., validate=False)` decorators for an :class:`Api` where `validate=True` is set on the constructor (:issue:`609`, :pr:`610`)
 - Ensure `basePath` is always a path
 - Hide Namespaces with all hidden Resources from Swagger documentation
+- In register_model() when working with SchemaModel type, also recursively register nested models
 
 0.12.1 (2018-09-28)
 -------------------
diff --git a/flask_restplus/swagger.py b/flask_restplus/swagger.py
index d98cb5d0..d355f9ad 100644
--- a/flask_restplus/swagger.py
+++ b/flask_restplus/swagger.py
@@ -16,7 +16,7 @@
 from werkzeug.routing import parse_rule
 
 from . import fields
-from .model import Model, ModelBase
+from .model import SchemaModel, Model, ModelBase
 from .reqparse import RequestParser
 from .utils import merge, not_none, not_none_sorted
 from ._http import HTTPStatus
@@ -557,6 +557,11 @@ def register_model(self, model):
         if isinstance(specs, Model):
             for field in itervalues(specs):
                 self.register_field(field)
+        if isinstance(specs, SchemaModel) and 'definitions' in specs._schema:
+            for key, defn in iteritems(specs._schema['definitions']):
+                if key not in self.api.models:
+                    self.register_model(self.api.schema_model(key, defn))
+            del(specs._schema['definitions'])
         return ref(model)
 
     def register_field(self, field):