diff --git a/packages/gateway-client/src/client.ts b/packages/gateway-client/src/client.ts
index 2aa0dfce9b4f..55273f0cf26b 100644
--- a/packages/gateway-client/src/client.ts
+++ b/packages/gateway-client/src/client.ts
@@ -1599,7 +1599,14 @@ export class GatewayClient {
       });
       signal?.addEventListener("abort", abortHandler, { once: true });
     });
-    this.ws.send(JSON.stringify(frame));
+    try {
+      this.ws.send(JSON.stringify(frame));
+    } catch (error) {
+      const pending = this.pending.get(id);
+      this.pending.delete(id);
+      pending?.cleanup?.();
+      throw error;
+    }
     return p;
   }
 }
diff --git a/packages/gateway-client/src/client.watchdog.test.ts b/packages/gateway-client/src/client.watchdog.test.ts
index 4d3b0e8a642a..2e565b2b7029 100644
--- a/packages/gateway-client/src/client.watchdog.test.ts
+++ b/packages/gateway-client/src/client.watchdog.test.ts
@@ -317,6 +317,27 @@ describe("GatewayClient", () => {
     }
   });
 
+  test("cleans pending request state when websocket send throws", async () => {
+    const client = new GatewayClient({
+      requestTimeoutMs: 25,
+    });
+    const sendError = new Error("synthetic send failure");
+    (
+      client as unknown as {
+        ws: WebSocket | { readyState: number; send: () => void; close: () => void };
+      }
+    ).ws = {
+      readyState: WebSocket.OPEN,
+      send: vi.fn(() => {
+        throw sendError;
+      }),
+      close: vi.fn(),
+    };
+
+    await expect(client.request("status")).rejects.toThrow("synthetic send failure");
+    expect(getPendingCount(client)).toBe(0);
+  });
+
   test("does not auto-timeout expectFinal requests", async () => {
     vi.useFakeTimers();
     try {