diff --git a/api-ref/source/v2/parameters.yaml b/api-ref/source/v2/parameters.yaml
index 80c167090..5ae685218 100644
--- a/api-ref/source/v2/parameters.yaml
+++ b/api-ref/source/v2/parameters.yaml
@@ -4277,6 +4277,18 @@ router-external_gateway_info-request:
   in: body
   required: false
   type: object
+router-flavor_id:
+  description: |
+    The ID of the flavor associated with the router.
+  in: body
+  required: true
+  type: string
+router-flavor_id-optional:
+  description: |
+    The ID of the flavor associated with the router.
+  in: body
+  required: false
+  type: string
 router-ha:
   description: |
     ``true`` indicates a highly-available router.
diff --git a/api-ref/source/v2/routers.inc b/api-ref/source/v2/routers.inc
index 4f6077d3a..cf9de9f62 100644
--- a/api-ref/source/v2/routers.inc
+++ b/api-ref/source/v2/routers.inc
@@ -23,6 +23,13 @@ The extra route extension (``extraroute``) extends ``router`` resources adding
 a ``routes`` attribute that contains an array of route objects. Each route
 object has a ``destination`` and ``nexthop`` attribute representing the route.
 
+L3 flavors extension (``l3-flavors``)
+=====================================
+
+The router flavor extension (``l3-flavors``) adds the ``flavor_id`` attribute
+to routers, allowing requests to be dispatched to different drivers depending
+on the flavor associated with a given router.
+
 Router availability zone extension
 ==================================
 
@@ -104,6 +111,7 @@ Response Parameters
    - availability_zone_hints: router-availability_zone_hints
    - availability_zones: router-availability_zones
    - service_type_id: router-service_type_id
+   - flavor_id: router-flavor_id
 
 Response Example
 ----------------
@@ -151,6 +159,7 @@ Request
    - ha: router-ha-request
    - availability_zone_hints: router-availability_zone_hints-request
    - service_type_id: router-service_type_id-request
+   - flavor_id: router-flavor_id-optional
 
 Request Example
 ---------------
@@ -184,6 +193,7 @@ Response Parameters
    - availability_zone_hints: router-availability_zone_hints
    - availability_zones: router-availability_zones
    - service_type_id: router-service_type_id
+   - flavor_id: router-flavor_id
 
 Response Example
 ----------------
@@ -242,6 +252,7 @@ Response Parameters
    - availability_zone_hints: router-availability_zone_hints
    - availability_zones: router-availability_zones
    - service_type_id: router-service_type_id
+   - flavor_id: router-flavor_id
 
 Response Example
 ----------------
@@ -312,6 +323,7 @@ Response Parameters
    - availability_zone_hints: router-availability_zone_hints
    - availability_zones: router-availability_zones
    - service_type_id: router-service_type_id
+   - flavor_id: router-flavor_id
 
 Response Example
 ----------------
diff --git a/api-ref/source/v2/samples/routers/router-create-response.json b/api-ref/source/v2/samples/routers/router-create-response.json
index 2d4179244..ee8a7278a 100644
--- a/api-ref/source/v2/samples/routers/router-create-response.json
+++ b/api-ref/source/v2/samples/routers/router-create-response.json
@@ -17,6 +17,7 @@
             ],
             "network_id": "ae34051f-aa6c-4c75-abf5-50dc9ac99ef3"
         },
+        "flavor_id": "f7b14d9a-b0dc-4fbe-bb14-a0f4970a69e0",
         "ha": false,
         "id": "f8a44de0-fc8e-45df-93c7-f79bf3b01c95",
         "name": "router1",
diff --git a/api-ref/source/v2/samples/routers/router-show-response.json b/api-ref/source/v2/samples/routers/router-show-response.json
index 20b88f23f..dc93bb24d 100644
--- a/api-ref/source/v2/samples/routers/router-show-response.json
+++ b/api-ref/source/v2/samples/routers/router-show-response.json
@@ -21,6 +21,7 @@
             ],
             "network_id": "ae34051f-aa6c-4c75-abf5-50dc9ac99ef3"
         },
+        "flavor_id": "f7b14d9a-b0dc-4fbe-bb14-a0f4970a69e0",
         "ha": false,
         "id": "f8a44de0-fc8e-45df-93c7-f79bf3b01c95",
         "name": "router1",
diff --git a/api-ref/source/v2/samples/routers/router-update-response.json b/api-ref/source/v2/samples/routers/router-update-response.json
index 6e806f3b8..003791c57 100644
--- a/api-ref/source/v2/samples/routers/router-update-response.json
+++ b/api-ref/source/v2/samples/routers/router-update-response.json
@@ -17,6 +17,7 @@
             ],
             "network_id": "ae34051f-aa6c-4c75-abf5-50dc9ac99ef3"
         },
+        "flavor_id": "f7b14d9a-b0dc-4fbe-bb14-a0f4970a69e0",
         "ha": false,
         "id": "f8a44de0-fc8e-45df-93c7-f79bf3b01c95",
         "name": "router1",
diff --git a/api-ref/source/v2/samples/routers/routers-list-response.json b/api-ref/source/v2/samples/routers/routers-list-response.json
index f16cf6190..499f71431 100644
--- a/api-ref/source/v2/samples/routers/routers-list-response.json
+++ b/api-ref/source/v2/samples/routers/routers-list-response.json
@@ -22,6 +22,7 @@
                 ],
                 "network_id": "ae34051f-aa6c-4c75-abf5-50dc9ac99ef3"
             },
+            "flavor_id": "f7b14d9a-b0dc-4fbe-bb14-a0f4970a69e0",
             "ha": false,
             "id": "915a14a6-867b-4af7-83d1-70efceb146f9",
             "name": "router2",
@@ -59,6 +60,7 @@
                 ],
                 "network_id": "ae34051f-aa6c-4c75-abf5-50dc9ac99ef3"
             },
+            "flavor_id": "f7b14d9a-b0dc-4fbe-bb14-a0f4970a69e0",
             "ha": false,
             "id": "f8a44de0-fc8e-45df-93c7-f79bf3b01c95",
             "name": "router1",