diff --git a/src/handlers/channels/THREAD_MEMBERS_UPDATE.ts b/src/handlers/channels/THREAD_MEMBERS_UPDATE.ts
new file mode 100644
index 000000000..b614f143e
--- /dev/null
+++ b/src/handlers/channels/THREAD_MEMBERS_UPDATE.ts
@@ -0,0 +1,19 @@
+import { eventHandlers } from "../../bot.ts";
+import { cacheHandlers } from "../../cache.ts";
+import { ThreadMembersUpdate } from "../../types/channels/threads/thread_members_update.ts";
+import { DiscordGatewayPayload } from "../../types/gateway/gateway_payload.ts";
+import { snowflakeToBigint } from "../../util/bigint.ts";
+
+export async function handleThreadMembersUpdate(data: DiscordGatewayPayload) {
+  const payload = data.d as ThreadMembersUpdate;
+  const thread = await cacheHandlers.get(
+    "channels",
+    snowflakeToBigint(payload.id),
+  );
+  if (!thread) return;
+
+  thread.memberCount = payload.memberCount;
+  await cacheHandlers.set("channels", thread.id, thread);
+
+  eventHandlers.threadMembersUpdate?.(payload);
+}