diff --git a/CHANGELOG.md b/CHANGELOG.md
index ceae883de..b0907b673 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -32,6 +32,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ### Fixed
 
 - Fixed GitHub pages ([#215](https://github.com/opensearch-project/opensearch-api-specification/pull/215))
+- Fixed missing 201 response in `/{index}/_doc/{id}` ([#331](https://github.com/opensearch-project/opensearch-api-specification/pull/331))
 
 ### Security
 
diff --git a/spec/namespaces/_core.yaml b/spec/namespaces/_core.yaml
index 2e1aeb6cb..a992acaed 100644
--- a/spec/namespaces/_core.yaml
+++ b/spec/namespaces/_core.yaml
@@ -1218,6 +1218,8 @@ paths:
       requestBody:
         $ref: '#/components/requestBodies/index'
       responses:
+        '201':
+          $ref: '#/components/responses/index@201'
         '200':
           $ref: '#/components/responses/index@200'
   /{index}/_doc/{id}:
@@ -1291,6 +1293,8 @@ paths:
       requestBody:
         $ref: '#/components/requestBodies/index'
       responses:
+        '201':
+          $ref: '#/components/responses/index@201'
         '200':
           $ref: '#/components/responses/index@200'
     put:
@@ -1317,6 +1321,8 @@ paths:
       requestBody:
         $ref: '#/components/requestBodies/index'
       responses:
+        '201':
+          $ref: '#/components/responses/index@201'
         '200':
           $ref: '#/components/responses/index@200'
     delete:
@@ -2875,6 +2881,12 @@ components:
         application/json:
           schema:
             $ref: '../schemas/_common.yaml#/components/schemas/WriteResponseBase'
+    index@201:
+      description: ''
+      content:
+        application/json:
+          schema:
+            $ref: '../schemas/_common.yaml#/components/schemas/WriteResponseBase'
     info@200:
       description: ''
       content:
diff --git a/tests/_core/index/_doc.yaml b/tests/_core/index/_doc.yaml
new file mode 100644
index 000000000..6b21f687b
--- /dev/null
+++ b/tests/_core/index/_doc.yaml
@@ -0,0 +1,49 @@
+$schema: ../../../json_schemas/test_story.schema.yaml
+
+skip: false
+description: Test inserting and retrieving a doc.
+epilogues:
+  - path: /movies
+    method: DELETE
+    status: [200, 404]
+chapters:
+  - synopsis: Create a document.
+    path: /{index}/_doc/{id}
+    method: POST
+    parameters:
+      index: movies
+      id: '1'
+    request_body:
+      payload:
+        title: Beauty and the Beast
+        year: 1991
+    response:
+      status: 201
+  - synopsis: Update a document.
+    path: /{index}/_doc/{id}
+    method: PUT
+    parameters:
+      index: movies
+      id: '1'
+    request_body:
+      payload:
+        title: Beauty and the Beast (Updated)
+        year: 1991
+    response:
+      status: 200
+  - synopsis: Retrieve a document.
+    path: /{index}/_doc/{id}
+    method: GET
+    parameters:
+      index: movies
+      id: '1'
+    response:
+      status: 200
+  - synopsis: Delete a document.
+    path: /{index}/_doc/{id}
+    method: DELETE
+    parameters:
+      index: movies
+      id: '1'
+    response:
+      status: 200