diff --git a/neutron_lib/api/definitions/l3.py b/neutron_lib/api/definitions/l3.py
index 740d770e1..755bb44af 100644
--- a/neutron_lib/api/definitions/l3.py
+++ b/neutron_lib/api/definitions/l3.py
@@ -96,10 +96,7 @@ RESOURCE_ATTRIBUTE_MAP = {
                                    'network_id': {'type:uuid': None,
                                                   'required': True},
                                    'external_fixed_ips': {
-                                       'convert_list_to':
-                                           converters.convert_kvp_list_to_dict,
                                        'type:fixed_ips': None,
-                                       'default': None,
                                        'required': False,
                                    }
                                }
diff --git a/neutron_lib/api/definitions/l3_ext_gw_mode.py b/neutron_lib/api/definitions/l3_ext_gw_mode.py
index 0a73b5481..7d3ca8fa6 100644
--- a/neutron_lib/api/definitions/l3_ext_gw_mode.py
+++ b/neutron_lib/api/definitions/l3_ext_gw_mode.py
@@ -42,9 +42,7 @@ RESOURCE_ATTRIBUTE_MAP = {
                                     'convert_to':
                                         converters.convert_to_boolean},
                     'external_fixed_ips': {
-                        'convert_list_to': converters.convert_kvp_list_to_dict,
                         'type:fixed_ips': None,
-                        'default': None,
                         'required': False
                     }
                 }
diff --git a/releasenotes/notes/cleanup-unused-l3-attr-def-f0eab40813d17a2d.yaml b/releasenotes/notes/cleanup-unused-l3-attr-def-f0eab40813d17a2d.yaml
new file mode 100644
index 000000000..685743b7c
--- /dev/null
+++ b/releasenotes/notes/cleanup-unused-l3-attr-def-f0eab40813d17a2d.yaml
@@ -0,0 +1,5 @@
+---
+other:
+  - |
+    The ``convert_list_to`` and ``default`` parameters of external_fixed_ips
+    have been removed from l3 and l3_ext_gw_mode API definitions.