diff --git a/toscaparser/tests/test_topology_template.py b/toscaparser/tests/test_topology_template.py
index b0c6d0f2..695aa93e 100644
--- a/toscaparser/tests/test_topology_template.py
+++ b/toscaparser/tests/test_topology_template.py
@@ -281,3 +281,103 @@ class TopologyTemplateTest(TestCase):
                           lambda: ToscaTemplate(tpl_path))
         exception.ExceptionCollector.assertExceptionMessage(
             KeyError, errormsg)
+
+    def test_invalid_type_policies(self):
+        tpl_snippet = '''
+        policies:
+           some_policy:
+              type: tosca.policies.Placement
+        '''
+        policies = (toscaparser.utils.yamlparser.simple_parse(tpl_snippet))
+        custom_defs = self._get_custom_types()
+        err = self.assertRaises(exception.TypeMismatchError,
+                                lambda: TopologyTemplate(policies,
+                                                         custom_defs))
+        errormsg = _('policies must be of type "list".')
+        self.assertEqual(errormsg, err.__str__())
+
+    def test_invalid_type_groups(self):
+        tpl_snippet = '''
+        groups:
+           - some_group:
+              type: tosca.groups.Root
+        '''
+        policies = (toscaparser.utils.yamlparser.simple_parse(tpl_snippet))
+        custom_defs = self._get_custom_types()
+        err = self.assertRaises(exception.TypeMismatchError,
+                                lambda: TopologyTemplate(policies,
+                                                         custom_defs))
+        errormsg = _('groups must be of type "dict".')
+        self.assertEqual(errormsg, err.__str__())
+
+    def test_invalid_type_substitution_mappings(self):
+        tpl_snippet = '''
+        substitution_mappings:
+           - node_type: MyService
+             properties:
+               num_cpus: cpus
+        '''
+        policies = (toscaparser.utils.yamlparser.simple_parse(tpl_snippet))
+        custom_defs = self._get_custom_types()
+        err = self.assertRaises(exception.TypeMismatchError,
+                                lambda: TopologyTemplate(policies,
+                                                         custom_defs))
+        errormsg = _('substitution_mappings must be of type "dict".')
+        self.assertEqual(errormsg, err.__str__())
+
+    def test_invalid_type_outputs(self):
+        tpl_snippet = '''
+        outputs:
+           - some_output:
+               value: some_value
+        '''
+        policies = (toscaparser.utils.yamlparser.simple_parse(tpl_snippet))
+        custom_defs = self._get_custom_types()
+        err = self.assertRaises(exception.TypeMismatchError,
+                                lambda: TopologyTemplate(policies,
+                                                         custom_defs))
+        errormsg = _('outputs must be of type "dict".')
+        self.assertEqual(errormsg, err.__str__())
+
+    def test_invalid_type_relationship_templates(self):
+        tpl_snippet = '''
+        relationship_templates:
+           - my_connection:
+                type: ConnectsTo
+        '''
+        policies = (toscaparser.utils.yamlparser.simple_parse(tpl_snippet))
+        custom_defs = self._get_custom_types()
+        err = self.assertRaises(exception.TypeMismatchError,
+                                lambda: TopologyTemplate(policies,
+                                                         custom_defs))
+        errormsg = _('relationship_templates must be of type "dict".')
+        self.assertEqual(errormsg, err.__str__())
+
+    def test_invalid_type_nodetemplates(self):
+        tpl_snippet = '''
+        node_templates:
+           - some_node:
+               type: tosca.nodes.Compute
+        '''
+        policies = (toscaparser.utils.yamlparser.simple_parse(tpl_snippet))
+        custom_defs = self._get_custom_types()
+        err = self.assertRaises(exception.TypeMismatchError,
+                                lambda: TopologyTemplate(policies,
+                                                         custom_defs))
+        errormsg = _('node_templates must be of type "dict".')
+        self.assertEqual(errormsg, err.__str__())
+
+    def test_invalid_type_inputs(self):
+        tpl_snippet = '''
+        inputs:
+           - some_input:
+               type: integer
+               value: 1
+        '''
+        policies = (toscaparser.utils.yamlparser.simple_parse(tpl_snippet))
+        custom_defs = self._get_custom_types()
+        err = self.assertRaises(exception.TypeMismatchError,
+                                lambda: TopologyTemplate(policies,
+                                                         custom_defs))
+        errormsg = _('inputs must be of type "dict".')
+        self.assertEqual(errormsg, err.__str__())
diff --git a/toscaparser/topology_template.py b/toscaparser/topology_template.py
index c4e99f3c..fb3dcb0c 100644
--- a/toscaparser/topology_template.py
+++ b/toscaparser/topology_template.py
@@ -212,25 +212,55 @@ class TopologyTemplate(object):
             return description.rstrip()
 
     def _tpl_inputs(self):
-        return self.tpl.get(INPUTS) or {}
+        inputs = self.tpl.get(INPUTS) or {}
+        if not isinstance(inputs, dict):
+            exception.ExceptionCollector.appendException(
+                exception.TypeMismatchError(what=INPUTS, type="dict"))
+        return inputs
 
     def _tpl_nodetemplates(self):
-        return self.tpl.get(NODE_TEMPLATES)
+        nodetemplates = self.tpl.get(NODE_TEMPLATES)
+        if nodetemplates and not isinstance(nodetemplates, dict):
+            exception.ExceptionCollector.appendException(
+                exception.TypeMismatchError(what=NODE_TEMPLATES, type="dict"))
+        return nodetemplates
 
     def _tpl_relationship_templates(self):
-        return self.tpl.get(RELATIONSHIP_TEMPLATES) or {}
+        relationship_templates = self.tpl.get(RELATIONSHIP_TEMPLATES) or {}
+        if not isinstance(relationship_templates, dict):
+            exception.ExceptionCollector.appendException(
+                exception.TypeMismatchError(what=RELATIONSHIP_TEMPLATES,
+                                            type="dict"))
+        return relationship_templates
 
     def _tpl_outputs(self):
-        return self.tpl.get(OUTPUTS) or {}
+        outputs = self.tpl.get(OUTPUTS) or {}
+        if not isinstance(outputs, dict):
+            exception.ExceptionCollector.appendException(
+                exception.TypeMismatchError(what=OUTPUTS, type="dict"))
+        return outputs
 
     def _tpl_substitution_mappings(self):
-        return self.tpl.get(SUBSTITUION_MAPPINGS) or {}
+        substitution_mappings = self.tpl.get(SUBSTITUION_MAPPINGS) or {}
+        if not isinstance(substitution_mappings, dict):
+            exception.ExceptionCollector.appendException(
+                exception.TypeMismatchError(what=SUBSTITUION_MAPPINGS,
+                                            type="dict"))
+        return substitution_mappings
 
     def _tpl_groups(self):
-        return self.tpl.get(GROUPS) or {}
+        groups = self.tpl.get(GROUPS) or {}
+        if not isinstance(groups, dict):
+            exception.ExceptionCollector.appendException(
+                exception.TypeMismatchError(what=GROUPS, type="dict"))
+        return groups
 
     def _tpl_policies(self):
-        return self.tpl.get(POLICIES) or {}
+        policies = self.tpl.get(POLICIES) or []
+        if not isinstance(policies, list):
+            exception.ExceptionCollector.appendException(
+                exception.TypeMismatchError(what=POLICIES, type="list"))
+        return policies
 
     def _validate_field(self):
         for name in self.tpl: