diff --git a/packages/connect-query/src/connect-query-key.ts b/packages/connect-query/src/connect-query-key.ts
index ba3db295..12d6ec8d 100644
--- a/packages/connect-query/src/connect-query-key.ts
+++ b/packages/connect-query/src/connect-query-key.ts
@@ -19,8 +19,8 @@ import type {
   ServiceType,
 } from "@bufbuild/protobuf";
 
-import type { DisableQuery } from "./utils";
-import { disableQuery } from "./utils";
+import type { DisableQuery } from "./utils.js";
+import { disableQuery } from "./utils.js";
 
 /**
  * TanStack Query requires query keys in order to decide when the query should automatically update.
diff --git a/packages/connect-query/src/create-query-functions.ts b/packages/connect-query/src/create-query-functions.ts
index 74b69728..65c1cfa6 100644
--- a/packages/connect-query/src/create-query-functions.ts
+++ b/packages/connect-query/src/create-query-functions.ts
@@ -21,9 +21,9 @@ import type {
 import { MethodKind } from "@bufbuild/protobuf";
 import type { Transport } from "@connectrpc/connect";
 
-import type { UnaryFunctions } from "./create-unary-functions";
-import { createUnaryFunctions } from "./create-unary-functions";
-import { unreachableCase } from "./utils";
+import type { UnaryFunctions } from "./create-unary-functions.js";
+import { createUnaryFunctions } from "./create-unary-functions.js";
+import { unreachableCase } from "./utils.js";
 
 /**
  * This is an array of supported `MethodKind`s
diff --git a/packages/connect-query/src/create-query-service.ts b/packages/connect-query/src/create-query-service.ts
index 87f0161a..52c8da8f 100644
--- a/packages/connect-query/src/create-query-service.ts
+++ b/packages/connect-query/src/create-query-service.ts
@@ -15,8 +15,8 @@
 import type { ServiceType } from "@bufbuild/protobuf";
 import type { Transport } from "@connectrpc/connect";
 
-import type { QueryFunctions } from "./create-query-functions";
-import { createQueryFunctions } from "./create-query-functions";
+import type { QueryFunctions } from "./create-query-functions.js";
+import { createQueryFunctions } from "./create-query-functions.js";
 
 const servicesToHooks = new Map<ServiceType, QueryFunctions<ServiceType>>();
 
diff --git a/packages/connect-query/src/create-unary-functions.ts b/packages/connect-query/src/create-unary-functions.ts
index 4c79e90c..c9053fea 100644
--- a/packages/connect-query/src/create-unary-functions.ts
+++ b/packages/connect-query/src/create-unary-functions.ts
@@ -27,16 +27,16 @@ import type {
 import type {
   ConnectPartialQueryKey,
   ConnectQueryKey,
-} from "./connect-query-key";
-import { makeConnectQueryKeyGetter } from "./connect-query-key";
-import type { DisableQuery } from "./utils";
+} from "./connect-query-key.js";
+import { makeConnectQueryKeyGetter } from "./connect-query-key.js";
+import type { DisableQuery } from "./utils.js";
 import {
   assert,
   disableQuery,
   isUnaryMethod,
   protobufSafeUpdater,
   unreachableCase,
-} from "./utils";
+} from "./utils.js";
 
 type RequireExactlyOne<T, Keys extends keyof T = keyof T> = {
   [K in Keys]-?: Partial<Record<Exclude<Keys, K>, undefined>> &
diff --git a/packages/connect-query/src/create-unary-hooks.ts b/packages/connect-query/src/create-unary-hooks.ts
index 67a90a75..01318564 100644
--- a/packages/connect-query/src/create-unary-hooks.ts
+++ b/packages/connect-query/src/create-unary-hooks.ts
@@ -14,8 +14,8 @@
 
 import type { Message } from "@bufbuild/protobuf";
 
-import type { UnaryFunctions } from "./create-unary-functions";
-import { useTransport } from "./use-transport";
+import type { UnaryFunctions } from "./create-unary-functions.js";
+import { useTransport } from "./use-transport.js";
 
 /**
  * All the additional hooks that are unique to React.
diff --git a/packages/connect-query/src/index.ts b/packages/connect-query/src/index.ts
index 622ff503..8a0896ac 100644
--- a/packages/connect-query/src/index.ts
+++ b/packages/connect-query/src/index.ts
@@ -14,31 +14,31 @@
 
 import type { Message } from "@bufbuild/protobuf";
 
-import type { UnaryFunctions } from "./create-unary-functions";
-import type { UnaryHooks } from "./create-unary-hooks";
+import type { UnaryFunctions } from "./create-unary-functions.js";
+import type { UnaryHooks } from "./create-unary-hooks.js";
 
-export { createQueryService } from "./create-query-service";
+export { createQueryService } from "./create-query-service.js";
 export type {
   QueryFunctions,
   SupportedMethodInfo,
   IsSupportedMethod,
   SupportedMethodKinds,
-} from "./create-query-functions";
+} from "./create-query-functions.js";
 export {
   createQueryFunctions,
   supportedMethodKinds,
   isSupportedMethod,
-} from "./create-query-functions";
+} from "./create-query-functions.js";
 export type {
   ConnectQueryKey,
   ConnectPartialQueryKey,
-} from "./connect-query-key";
-export type { UnaryFunctions } from "./create-unary-functions";
-export { createUnaryFunctions } from "./create-unary-functions";
-export { disableQuery } from "./utils";
-export { useTransport, TransportProvider } from "./use-transport";
-export type { UnaryHooks } from "./create-unary-hooks";
-export { createUnaryHooks } from "./create-unary-hooks";
+} from "./connect-query-key.js";
+export type { UnaryFunctions } from "./create-unary-functions.js";
+export { createUnaryFunctions } from "./create-unary-functions.js";
+export { disableQuery } from "./utils.js";
+export { useTransport, TransportProvider } from "./use-transport.js";
+export type { UnaryHooks } from "./create-unary-hooks.js";
+export { createUnaryHooks } from "./create-unary-hooks.js";
 
 /**
  * Combined type of all the functions generated for a service.