diff --git a/nova/objects/resource_provider.py b/nova/objects/resource_provider.py
index d5fe044bb995..7896cfef6ab0 100644
--- a/nova/objects/resource_provider.py
+++ b/nova/objects/resource_provider.py
@@ -544,7 +544,11 @@ class InventoryList(base.ObjectListBase, base.NovaObject):
                           string.
         """
         if isinstance(res_class, six.string_types):
-            res_class = fields.ResourceClass.index(res_class)
+            try:
+                res_class = fields.ResourceClass.index(res_class)
+            except ValueError:
+                raise exception.NotFound("No such resource class '%s'" %
+                                         res_class)
 
         for inv_rec in self.objects:
             if fields.ResourceClass.index(inv_rec.resource_class) == res_class:
diff --git a/nova/tests/functional/api/openstack/placement/gabbits/inventory.yaml b/nova/tests/functional/api/openstack/placement/gabbits/inventory.yaml
index b21a6d13eadc..e594c3f3705a 100644
--- a/nova/tests/functional/api/openstack/placement/gabbits/inventory.yaml
+++ b/nova/tests/functional/api/openstack/placement/gabbits/inventory.yaml
@@ -239,6 +239,10 @@ tests:
   GET: /resource_providers/$ENVIRON['RP_UUID']/inventories/IPV4_ADDRESS
   status: 404
 
+- name: get invalid inventory class
+  GET: /resource_providers/$ENVIRON['RP_UUID']/inventories/HOUSE
+  status: 404
+
 - name: create another resource provider
   POST: /resource_providers
   request_headers:
diff --git a/nova/tests/unit/objects/test_resource_provider.py b/nova/tests/unit/objects/test_resource_provider.py
index 1dc4813f5a60..910b3f556bca 100644
--- a/nova/tests/unit/objects/test_resource_provider.py
+++ b/nova/tests/unit/objects/test_resource_provider.py
@@ -435,6 +435,12 @@ class TestInventory(test_objects._LocalTest):
         self.assertIsNotNone(found)
         self.assertEqual(24, found.total)
 
+        # Use an invalid string...
+        error = self.assertRaises(exception.NotFound,
+                                  inv_list.find,
+                                  'HOUSE')
+        self.assertIn('No such resource class', str(error))
+
 
 class _TestAllocationNoDB(object):
     @mock.patch('nova.objects.Allocation._create_in_db',