diff --git a/osp/core/ontology/namespace.py b/osp/core/ontology/namespace.py
index 24cfa482..e92049e9 100644
--- a/osp/core/ontology/namespace.py
+++ b/osp/core/ontology/namespace.py
@@ -187,9 +187,10 @@ def _do_get(self, name, _case_sensitive, _force_by_iri):
         iri = rdflib.URIRef(str(self._iri) + iri_suffix)
         try:
             return self._namespace_registry.from_iri(iri, _name=name)
-        except ValueError:
-            return self._get_case_insensitive(name)
-        return self._get_case_insensitive(name)
+        except KeyError as e:
+            if not _case_sensitive:
+                return self._get_case_insensitive(name)
+            raise e
 
     def _get_case_insensitive(self, name):
         """Get by trying alternative naming convention of given name.
diff --git a/tests/test_case_insensitivity.py b/tests/test_case_insensitivity.py
index 35fa206d..9d3a685a 100644
--- a/tests/test_case_insensitivity.py
+++ b/tests/test_case_insensitivity.py
@@ -26,6 +26,9 @@ def test_get_case_insensitive_alternative(self):
         self.assertEqual(alt("some_entity", False), "SOME_ENTITY")
         self.assertEqual(alt("SOME_ENTITY", False), "SOME_ENTITY")
 
+        from osp.core.namespaces import cuba
+        self.assertEqual(cuba.wrapper, cuba.Wrapper)
+
 
 if __name__ == "__main__":
     unittest.main()