diff --git a/CHANGELOG.md b/CHANGELOG.md
index 55248104d..33fd247e2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -63,6 +63,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Fixed optional field in `/_nodes` ([#365](https://github.com/opensearch-project/opensearch-api-specification/pull/365))
 - Fixed `/{index}/_open` can return a `task` ([#376](https://github.com/opensearch-project/opensearch-api-specification/pull/376))
 - Fixed `_source` in `bulk` responses ([#375](https://github.com/opensearch-project/opensearch-api-specification/pull/375))
+- Fixed `/_mapping` with index in query ([#385](https://github.com/opensearch-project/opensearch-api-specification/pull/385))
 
 ### Security
 
diff --git a/spec/namespaces/indices.yaml b/spec/namespaces/indices.yaml
index 2bda325dc..f23664b4c 100644
--- a/spec/namespaces/indices.yaml
+++ b/spec/namespaces/indices.yaml
@@ -413,6 +413,7 @@ paths:
       externalDocs:
         url: https://opensearch.org/docs/latest/field-types/index/#get-a-mapping
       parameters:
+        - $ref: '#/components/parameters/indices.get_mapping::query.index'
         - $ref: '#/components/parameters/indices.get_mapping::query.allow_no_indices'
         - $ref: '#/components/parameters/indices.get_mapping::query.cluster_manager_timeout'
         - $ref: '#/components/parameters/indices.get_mapping::query.expand_wildcards'
@@ -3780,6 +3781,16 @@ components:
       schema:
         $ref: '../schemas/_common.yaml#/components/schemas/Indices'
       style: simple
+    indices.get_mapping::query.index:
+      in: query
+      name: index
+      description: |-
+        Comma-separated list of data streams, indices, and aliases used to limit
+        the request. Supports wildcards (`*`). To target all data streams and
+        indices, omit this parameter or use `*` or `_all`.
+      schema:
+        type: string
+      style: form
     indices.get_mapping::query.allow_no_indices:
       in: query
       name: allow_no_indices
diff --git a/tests/_core/mapping.yaml b/tests/_core/mapping.yaml
new file mode 100644
index 000000000..05f854326
--- /dev/null
+++ b/tests/_core/mapping.yaml
@@ -0,0 +1,54 @@
+$schema: ../../json_schemas/test_story.schema.yaml
+
+description: Test mappings endpoints.
+prologues:
+  - path: /{index}
+    method: PUT
+    parameters:
+      index: movies
+    request_body:
+      payload:
+        mappings:
+          properties:
+            director:
+              type: text
+            year:
+              type: integer
+            location:
+              type: ip
+              ignore_malformed: true
+epilogues:
+  - path: /movies
+    method: DELETE
+    status: [200, 404]
+chapters:
+  - synopsis: Get mappings for an index (index in query).
+    path: /_mapping
+    method: GET
+    parameters:
+      index: movies
+    response:
+      status: 200
+      payload:
+        movies:
+          mappings:
+            properties:
+              director:
+                type: text
+              year:
+                type: integer
+  - synopsis: Get mappings for an index (index in path).
+    path: /{index}/_mapping
+    method: GET
+    parameters:
+      index: movies
+    response:
+      status: 200
+      payload:
+        movies:
+          mappings:
+            properties:
+              director:
+                type: text
+              year:
+                type: integer