diff --git a/.changeset/migrate-chat-getPinnedMessages.md b/.changeset/migrate-chat-getPinnedMessages.md
new file mode 100644
index 0000000000000..bd630a1eff53c
--- /dev/null
+++ b/.changeset/migrate-chat-getPinnedMessages.md
@@ -0,0 +1,6 @@
+---
+"@rocket.chat/meteor": minor
+"@rocket.chat/rest-typings": minor
+---
+
+Add OpenAPI support for the chat.getPinnedMessages API endpoint by migrating to a modern chained route definition syntax and utilizing AJV schemas for query and response validation.
diff --git a/apps/meteor/app/api/server/v1/chat.ts b/apps/meteor/app/api/server/v1/chat.ts
index a00d57e46ae72..19274096a5e9f 100644
--- a/apps/meteor/app/api/server/v1/chat.ts
+++ b/apps/meteor/app/api/server/v1/chat.ts
@@ -15,7 +15,6 @@ import {
 	isChatSearchProps,
 	isChatSendMessageProps,
 	isChatIgnoreUserProps,
-	isChatGetPinnedMessagesProps,
 	isChatGetMentionedMessagesProps,
 	isChatReactProps,
 	isChatGetDeletedMessagesProps,
@@ -275,6 +274,39 @@ const isChatPinMessageProps = ajv.compile<ChatPinMessage>(ChatPinMessageSchema);
 
 const isChatUnpinMessageProps = ajv.compile<ChatUnpinMessage>(ChatUnpinMessageSchema);
 
+type GetPinnedMessages = {
+	roomId: string;
+	count?: number;
+	offset?: number;
+	sort?: string;
+};
+
+const GetPinnedMessagesSchema = {
+	type: 'object',
+	properties: {
+		roomId: {
+			type: 'string',
+			minLength: 1,
+		},
+		count: {
+			type: 'number',
+			nullable: true,
+		},
+		offset: {
+			type: 'number',
+			nullable: true,
+		},
+		sort: {
+			type: 'string',
+			nullable: true,
+		},
+	},
+	required: ['roomId'],
+	additionalProperties: false,
+};
+
+const isChatGetPinnedMessagesProps = ajv.compile<GetPinnedMessages>(GetPinnedMessagesSchema);
+
 const chatEndpoints = API.v1
 	.post(
 		'chat.pinMessage',
@@ -558,6 +590,61 @@ const chatEndpoints = API.v1
 
 			return API.v1.success();
 		},
+	)
+	.get(
+		'chat.getPinnedMessages',
+		{
+			authRequired: true,
+			query: isChatGetPinnedMessagesProps,
+			response: {
+				200: ajv.compile<{ messages: IMessage[]; count: number; offset: number; total: number }>({
+					type: 'object',
+					properties: {
+						messages: {
+							type: 'array',
+							items: {
+								$ref: '#/components/schemas/IMessage',
+							},
+						},
+						count: { type: 'number' },
+						offset: { type: 'number' },
+						total: { type: 'number' },
+						success: {
+							type: 'boolean',
+							enum: [true],
+						},
+					},
+					required: ['messages', 'count', 'offset', 'total', 'success'],
+					additionalProperties: false,
+				}),
+				400: validateBadRequestErrorResponse,
+				401: validateUnauthorizedErrorResponse,
+			},
+		},
+		async function action() {
+			const { roomId } = this.queryParams;
+			const { offset, count } = await getPaginationItems(this.queryParams);
+			const { sort } = await this.parseJsonQuery();
+
+			if (!(await canAccessRoomIdAsync(roomId, this.userId))) {
+				throw new Meteor.Error('error-not-allowed', 'Not allowed');
+			}
+
+			const { cursor, totalCount } = Messages.findPaginatedPinnedByRoom(roomId, {
+				skip: offset,
+				limit: count,
+				sort,
+			});
+
+			const [messages, total] = await Promise.all([cursor.toArray(), totalCount]);
+
+			return API.v1.success({
+				messages: await normalizeMessagesForUser(messages, this.userId),
+				count: messages.length,
+				offset,
+				total,
+			});
+		},
 	);
 
 API.v1.addRoute(
@@ -753,35 +840,6 @@ API.v1.addRoute(
 	},
 );
 
-API.v1.addRoute(
-	'chat.getPinnedMessages',
-	{ authRequired: true, validateParams: isChatGetPinnedMessagesProps },
-	{
-		async get() {
-			const { roomId } = this.queryParams;
-			const { offset, count } = await getPaginationItems(this.queryParams);
-
-			if (!(await canAccessRoomIdAsync(roomId, this.userId))) {
-				throw new Meteor.Error('error-not-allowed', 'Not allowed');
-			}
-
-			const { cursor, totalCount } = Messages.findPaginatedPinnedByRoom(roomId, {
-				skip: offset,
-				limit: count,
-			});
-
-			const [messages, total] = await Promise.all([cursor.toArray(), totalCount]);
-
-			return API.v1.success({
-				messages: await normalizeMessagesForUser(messages, this.userId),
-				count: messages.length,
-				offset,
-				total,
-			});
-		},
-	},
-);
-
 API.v1.addRoute(
 	'chat.getThreadsList',
 	{ authRequired: true, validateParams: isChatGetThreadsListProps },
diff --git a/packages/rest-typings/src/v1/chat.ts b/packages/rest-typings/src/v1/chat.ts
index b52bba2d61ed5..cd29150b01b54 100644
--- a/packages/rest-typings/src/v1/chat.ts
+++ b/packages/rest-typings/src/v1/chat.ts
@@ -529,39 +529,6 @@ const GetStarredMessagesSchema = {
 
 export const isChatGetStarredMessagesProps = ajv.compile<GetStarredMessages>(GetStarredMessagesSchema);
 
-type GetPinnedMessages = {
-	roomId: IRoom['_id'];
-	count?: number;
-	offset?: number;
-	sort?: string;
-};
-
-const GetPinnedMessagesSchema = {
-	type: 'object',
-	properties: {
-		roomId: {
-			type: 'string',
-			minLength: 1,
-		},
-		count: {
-			type: 'number',
-			nullable: true,
-		},
-		offset: {
-			type: 'number',
-			nullable: true,
-		},
-		sort: {
-			type: 'string',
-			nullable: true,
-		},
-	},
-	required: ['roomId'],
-	additionalProperties: false,
-};
-
-export const isChatGetPinnedMessagesProps = ajv.compile<GetPinnedMessages>(GetPinnedMessagesSchema);
-
 type GetMentionedMessages = {
 	roomId: IRoom['_id'];
 	count?: number;
@@ -954,14 +921,6 @@ export type ChatEndpoints = {
 			total: number;
 		};
 	};
-	'/v1/chat.getPinnedMessages': {
-		GET: (params: GetPinnedMessages) => {
-			messages: IMessage[];
-			count: number;
-			offset: number;
-			total: number;
-		};
-	};
 	'/v1/chat.getMentionedMessages': {
 		GET: (params: GetMentionedMessages) => {
 			messages: IMessage[];