diff --git a/packages/vinext/src/plugins/optimize-imports.ts b/packages/vinext/src/plugins/optimize-imports.ts
index 4c7b1757f2..aaef84d029 100644
--- a/packages/vinext/src/plugins/optimize-imports.ts
+++ b/packages/vinext/src/plugins/optimize-imports.ts
@@ -49,6 +49,17 @@ type BarrelExportEntry = {
   source: string;
   isNamespace: boolean;
   originalName?: string;
+  /**
+   * The outermost module on the way to `source` that RSC replaces with
+   * references or wrappers because of its directive. RSC must import the name
+   * from it instead.
+   */
+  rscBoundary?: string;
+  /**
+   * The same for SSR, where only "use server" and "use cache" modules are
+   * replaced with references.
+   */
+  ssrBoundary?: string;
 };
 
 type BarrelExportMap = Map<string, BarrelExportEntry>;
@@ -398,7 +409,7 @@ async function buildExportMapFromFile(
   }
 
   const exportMap: BarrelExportMap = new Map();
-  const isBoundary = findBoundaryDirective(ast) !== null;
+  const boundaryDirective = findBoundaryDirective(ast);
 
   // Track import bindings: local name → { source, isNamespace, originalName }
   const importBindings = new Map<
@@ -614,11 +625,17 @@ async function buildExportMapFromFile(
     }
   }
 
-  if (isBoundary) {
-    // Every name a boundary module exports must be imported from the module
-    // itself, including names reached through `export *` into or out of it.
-    for (const name of exportMap.keys()) {
-      exportMap.set(name, { source: filePath, isNamespace: false, originalName: name });
+  if (boundaryDirective) {
+    // Record this module as the boundary for every name it exports, including
+    // names reached through `export *` into or out of it. Outer modules
+    // override inner ones, since an importer reaches them first.
+    const isSsrBoundary = boundaryDirective !== "use client";
+    for (const [name, entry] of exportMap) {
+      exportMap.set(name, {
+        ...entry,
+        rscBoundary: filePath,
+        ssrBoundary: isSsrBoundary ? filePath : entry.ssrBoundary,
+      });
     }
   }
 
@@ -759,14 +776,12 @@ export function createOptimizeImportsPlugin(
       // In pnpm strict mode, sub-packages like @radix-ui/react-slot are only
       // resolvable from the barrel package's location, not from user code.
       // Use Vite's own resolver (not createRequire) so it picks the ESM entry.
-      // subpkgOrigin is keyed by environment; prefer the current env's map but
-      // fall back to the other env's map for the case where only one environment
-      // has transformed files that import from a given barrel (e.g. a barrel
-      // only reachable from the RSC graph may still need resolving from SSR).
-      const envName = (this as PluginCtx).environment?.name ?? "ssr";
-      const barrelEntry =
-        barrelCaches.subpkgOrigin.get(envName)?.get(source) ??
-        barrelCaches.subpkgOrigin.get(envName === "rsc" ? "ssr" : "rsc")?.get(source);
+      // subpkgOrigin is keyed like the transform below, which registers every
+      // specifier it emits in its own environment's map. The other environment's
+      // map may hold specifiers this one never emits, such as packages behind a
+      // "use client" boundary in RSC.
+      const envKey = (this as PluginCtx).environment?.name === "rsc" ? "rsc" : "ssr";
+      const barrelEntry = barrelCaches.subpkgOrigin.get(envKey)?.get(source);
       if (!barrelEntry) return;
       const resolved = await this.resolve(source, barrelEntry, { skipSelf: true });
       return resolved ?? undefined;
@@ -852,6 +867,13 @@ export function createOptimizeImportsPlugin(
             barrelCaches.exportMapCache,
           );
           if (!exportMap || !barrelEntry) continue;
+          // The module to import a name from in this environment, stopping at
+          // the module that this environment replaces with references.
+          const getEntry = (name: string): BarrelExportEntry | undefined => {
+            const entry = exportMap.get(name);
+            const boundary = preferReactServer ? entry?.rscBoundary : entry?.ssrBoundary;
+            return boundary ? { source: boundary, isNamespace: false, originalName: name } : entry;
+          };
 
           // Register sub-package sources so resolveId can find them from
           // the barrel's context (needed for pnpm strict hoisting).
@@ -876,16 +898,15 @@ export function createOptimizeImportsPlugin(
               envOriginMap = new Map<string, string>();
               barrelCaches.subpkgOrigin.set(envKey, envOriginMap);
             }
-            for (const entry of exportMap.values()) {
-              if (
-                !entry.source.startsWith("/") &&
-                !entry.source.startsWith(".") &&
-                !envOriginMap.has(entry.source)
-              ) {
+            for (const name of exportMap.keys()) {
+              // Only the sources this environment can emit, so a package behind
+              // a boundary isn't registered.
+              const source = getEntry(name)!.source;
+              if (!source.startsWith("/") && !source.startsWith(".") && !envOriginMap.has(source)) {
                 // First barrel to register this specifier (within this environment) wins.
                 // Sub-package specifiers are keyed per environment so that RSC and SSR
                 // barrel entries don't cross-contaminate each other's resolution context.
-                envOriginMap.set(entry.source, barrelEntry);
+                envOriginMap.set(source, barrelEntry);
               }
             }
           }
@@ -952,7 +973,7 @@ export function createOptimizeImportsPlugin(
           // name gains nothing from a rewrite.
           if (
             isSubpath &&
-            specifiers.every(({ imported }) => exportMap.get(imported)?.source === barrelEntry)
+            specifiers.every(({ imported }) => getEntry(imported)?.source === barrelEntry)
           ) {
             continue;
           }
@@ -962,7 +983,7 @@ export function createOptimizeImportsPlugin(
           const resolvedPackageSources = new Map<string, string>();
           if (isSubpath) {
             for (const { imported } of specifiers) {
-              const source = exportMap.get(imported)?.source;
+              const source = getEntry(imported)?.source;
               if (!source || path.isAbsolute(source) || resolvedPackageSources.has(source))
                 continue;
               const resolvedId = await resolveFileId(this, source, barrelEntry);
@@ -985,7 +1006,7 @@ export function createOptimizeImportsPlugin(
             }
           >();
           for (const { local, imported } of specifiers) {
-            const entry = exportMap.get(imported);
+            const entry = getEntry(imported);
             if (!entry) continue;
             // Sources in the export map are already absolute paths (for file references)
             // or bare package specifiers — no further resolution needed.
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 08a2d8d51b..fb10597796 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -1451,6 +1451,9 @@ importers:
       '@vitejs/plugin-rsc':
         specifier: 'catalog:'
         version: 0.5.38(@voidzero-dev/vite-plus-core@1.1.0(@types/node@25.9.2)(esbuild@0.28.1)(jiti@2.7.0)(sass@1.100.0)(tsx@4.21.1)(typescript@7.0.2)(yaml@2.9.0))(react-dom@19.3.1(react@19.3.1))(react-server-dom-webpack@19.3.1(react-dom@19.3.1(react@19.3.1))(react@19.3.1))(react@19.3.1)
+      fake-client-barrel:
+        specifier: file:./__test_packages__/fake-client-barrel
+        version: file:tests/fixtures/app-basic/__test_packages__/fake-client-barrel
       fake-context-lib:
         specifier: file:./__test_packages__/fake-context-lib
         version: file:tests/fixtures/app-basic/__test_packages__/fake-context-lib
@@ -8458,6 +8461,9 @@ packages:
   extendable-error@0.1.7:
     resolution: {integrity: sha512-UOiS2in6/Q0FK0R0q6UY9vYpQ21mr/Qn1KOnte7vsACuNJf514WvCCUHSRCPcgjPT2bAhNIJdlE6bVap1GKmeg==}
 
+  fake-client-barrel@file:tests/fixtures/app-basic/__test_packages__/fake-client-barrel:
+    resolution: {directory: tests/fixtures/app-basic/__test_packages__/fake-client-barrel, type: directory}
+
   fake-context-lib@file:tests/fixtures/app-basic/__test_packages__/fake-context-lib:
     resolution: {directory: tests/fixtures/app-basic/__test_packages__/fake-context-lib, type: directory}
 
@@ -16933,6 +16939,8 @@ snapshots:
 
   extendable-error@0.1.7: {}
 
+  fake-client-barrel@file:tests/fixtures/app-basic/__test_packages__/fake-client-barrel: {}
+
   fake-context-lib@file:tests/fixtures/app-basic/__test_packages__/fake-context-lib: {}
 
   fake-css-lib@file:tests/fixtures/app-basic/__test_packages__/fake-css-lib: {}
diff --git a/tests/after-response-close-worker.test.ts b/tests/after-response-close-worker.test.ts
index aea6b9bee9..9ac73f94ca 100644
--- a/tests/after-response-close-worker.test.ts
+++ b/tests/after-response-close-worker.test.ts
@@ -57,10 +57,11 @@ describe("closeAfterResponseWithBody on the Cloudflare Workers runtime", () => {
       // createIsolatedFixture swaps in a plain workspace node_modules symlink
       // (here, cf-app-basic's, for @cloudflare/vite-plugin + wrangler), which
       // drops app-basic's own `file:./__test_packages__/*` local packages.
-      // Exclude the four routes that depend on those — unrelated to this
+      // Exclude the routes that depend on those — unrelated to this
       // regression — so the rest of the fixture still builds.
       (src) =>
         !src.includes(`${path.sep}app${path.sep}context-dedup-test`) &&
+        !src.includes(`${path.sep}app${path.sep}optimize-imports-client-barrel`) &&
         !src.includes(`${path.sep}app${path.sep}nextjs-compat${path.sep}node-modules-css`) &&
         !src.includes(
           `${path.sep}app${path.sep}nextjs-compat${path.sep}dynamic${path.sep}out-of-root-package`,
diff --git a/tests/e2e/app-router/optimize-imports-client-barrel.spec.ts b/tests/e2e/app-router/optimize-imports-client-barrel.spec.ts
new file mode 100644
index 0000000000..119501c47e
--- /dev/null
+++ b/tests/e2e/app-router/optimize-imports-client-barrel.spec.ts
@@ -0,0 +1,24 @@
+import { test, expect } from "@playwright/test";
+import { waitForAppRouterHydration } from "../helpers";
+
+const BASE = "http://localhost:4174";
+
+// fake-client-barrel is in the fixture's optimizePackageImports. Its entry is a
+// "use client" barrel, and its unused leaf sets a global when it is evaluated.
+test.describe('optimizePackageImports with a "use client" barrel', () => {
+  test("SSR only evaluates the modules that define the imported names", async ({ request }) => {
+    const res = await request.get(`${BASE}/optimize-imports-client-barrel`);
+    expect(res.status()).toBe(200);
+    const html = await res.text();
+    expect(html).toContain('data-testid="client-barrel-counter"');
+    expect(html).toContain('data-unused-loaded="false"');
+  });
+
+  test("the component hydrates", async ({ page }) => {
+    await page.goto(`${BASE}/optimize-imports-client-barrel`);
+    await waitForAppRouterHydration(page);
+    const counter = page.getByTestId("client-barrel-counter");
+    await counter.click();
+    await expect(counter).toHaveText("Count: 1");
+  });
+});
diff --git a/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/counter.js b/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/counter.js
new file mode 100644
index 0000000000..7529e54d0d
--- /dev/null
+++ b/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/counter.js
@@ -0,0 +1,16 @@
+import { createElement, useState } from "react";
+
+export function Counter() {
+  const [count, setCount] = useState(0);
+  return createElement(
+    "button",
+    {
+      "data-testid": "client-barrel-counter",
+      // Hydration can't match: the client loads the whole barrel.
+      "data-unused-loaded": String(globalThis.__fakeClientBarrelUnusedLoaded === true),
+      suppressHydrationWarning: true,
+      onClick: () => setCount((value) => value + 1),
+    },
+    `Count: ${count}`,
+  );
+}
diff --git a/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/index.js b/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/index.js
new file mode 100644
index 0000000000..a94604604d
--- /dev/null
+++ b/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/index.js
@@ -0,0 +1,5 @@
+"use client";
+
+// A "use client" barrel, like antd's entry.
+export { Counter } from "./counter.js";
+export { Unused } from "./unused.js";
diff --git a/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/package.json b/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/package.json
new file mode 100644
index 0000000000..8cc882913e
--- /dev/null
+++ b/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "fake-client-barrel",
+  "version": "1.0.0",
+  "private": true,
+  "type": "module",
+  "sideEffects": false,
+  "main": "index.js",
+  "exports": {
+    ".": "./index.js"
+  }
+}
diff --git a/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/unused.js b/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/unused.js
new file mode 100644
index 0000000000..003fe1da5b
--- /dev/null
+++ b/tests/fixtures/app-basic/__test_packages__/fake-client-barrel/unused.js
@@ -0,0 +1,5 @@
+globalThis.__fakeClientBarrelUnusedLoaded = true;
+
+export function Unused() {
+  return null;
+}
diff --git a/tests/fixtures/app-basic/app/optimize-imports-client-barrel/page.tsx b/tests/fixtures/app-basic/app/optimize-imports-client-barrel/page.tsx
new file mode 100644
index 0000000000..74037ed77d
--- /dev/null
+++ b/tests/fixtures/app-basic/app/optimize-imports-client-barrel/page.tsx
@@ -0,0 +1,7 @@
+"use client";
+
+import { Counter } from "fake-client-barrel";
+
+export default function OptimizeImportsClientBarrelPage() {
+  return <Counter />;
+}
diff --git a/tests/fixtures/app-basic/next.config.ts b/tests/fixtures/app-basic/next.config.ts
index b534d8177f..ea25e3300e 100644
--- a/tests/fixtures/app-basic/next.config.ts
+++ b/tests/fixtures/app-basic/next.config.ts
@@ -32,6 +32,9 @@ const nextConfig: NextConfig = {
   // don't assert the method's absence against this fixture.
   experimental: {
     gestureTransition: true,
+    // Used by E2E: optimize-imports-client-barrel.spec.ts — a "use client"
+    // barrel whose imports SSR rewrites to the modules that define them.
+    optimizePackageImports: ["fake-client-barrel"],
   },
 
   // Used by Vitest: app-router-production-server.test.ts — a next/dynamic()
diff --git a/tests/fixtures/app-basic/package.json b/tests/fixtures/app-basic/package.json
index 7de39b89ca..6ceaef0650 100644
--- a/tests/fixtures/app-basic/package.json
+++ b/tests/fixtures/app-basic/package.json
@@ -4,6 +4,7 @@
   "type": "module",
   "dependencies": {
     "@vitejs/plugin-rsc": "catalog:",
+    "fake-client-barrel": "file:./__test_packages__/fake-client-barrel",
     "fake-context-lib": "file:./__test_packages__/fake-context-lib",
     "fake-css-lib": "file:./__test_packages__/fake-css-lib",
     "fake-css-module-lib": "file:./__test_packages__/fake-css-module-lib",
diff --git a/tests/optimize-imports.test.ts b/tests/optimize-imports.test.ts
index 5ac33b04ba..4d4e49a053 100644
--- a/tests/optimize-imports.test.ts
+++ b/tests/optimize-imports.test.ts
@@ -391,28 +391,47 @@ export { Mo as Listbox };`;
     expect(map!.get("parse")).toBeDefined();
   });
 
-  it("does not follow re-exports through a directive boundary", async () => {
+  it("records the directive boundaries that re-exports pass through", async () => {
     const entryPath = "/fake/wildcard-boundary/index.js";
     const files: Record<string, string> = {
-      [entryPath]: `export * from "./client.js";\nexport { Button } from "./button.js";`,
-      "/fake/wildcard-boundary/client.js": `"use client";\nexport { Dialog } from "./dialog.js";\nexport * as Icons from "./icons.js";`,
+      [entryPath]: `export * from "./client.js";\nexport * from "./actions.js";\nexport { Button } from "./button.js";`,
+      "/fake/wildcard-boundary/client.js": `"use client";\nexport { Dialog } from "./dialog.js";\nexport * as Icons from "./icons.js";\nexport * from "./client-actions.js";`,
+      "/fake/wildcard-boundary/client-actions.js": `"use server";\nexport { save } from "./save.js";`,
+      "/fake/wildcard-boundary/actions.js": `"use server";\nexport { submit } from "./submit.js";`,
     };
 
     const map = await buildBarrelExportMap(entryPath, (fp) => Promise.resolve(files[fp] ?? null));
 
-    // Names exported by the "use client" module are imported from it, so the
-    // client reference boundary is kept.
+    // RSC stops at any directive; SSR only at "use server" and "use cache".
     expect(map!.get("Dialog")).toEqual({
-      source: "/fake/wildcard-boundary/client.js",
+      source: "/fake/wildcard-boundary/dialog.js",
       isNamespace: false,
       originalName: "Dialog",
+      rscBoundary: "/fake/wildcard-boundary/client.js",
+      ssrBoundary: undefined,
     });
     expect(map!.get("Icons")).toEqual({
-      source: "/fake/wildcard-boundary/client.js",
+      source: "/fake/wildcard-boundary/icons.js",
+      isNamespace: true,
+      rscBoundary: "/fake/wildcard-boundary/client.js",
+      ssrBoundary: undefined,
+    });
+    // The outermost boundary wins for each environment.
+    expect(map!.get("save")).toMatchObject({
+      source: "/fake/wildcard-boundary/save.js",
+      rscBoundary: "/fake/wildcard-boundary/client.js",
+      ssrBoundary: "/fake/wildcard-boundary/client-actions.js",
+    });
+    expect(map!.get("submit")).toMatchObject({
+      source: "/fake/wildcard-boundary/submit.js",
+      rscBoundary: "/fake/wildcard-boundary/actions.js",
+      ssrBoundary: "/fake/wildcard-boundary/actions.js",
+    });
+    expect(map!.get("Button")).toEqual({
+      source: "/fake/wildcard-boundary/button.js",
       isNamespace: false,
-      originalName: "Icons",
+      originalName: "Button",
     });
-    expect(map!.get("Button")!.source).toBe("/fake/wildcard-boundary/button.js");
   });
 
   it("does not overwrite existing exports when wildcard sub-module has same name", async () => {
@@ -632,7 +651,9 @@ describe("vinext:optimize-imports transform", () => {
   async function setupTransform(
     packageName: string,
     barrelContents: string,
-  ): Promise<(code: string, id: string) => Promise<ReturnType<(...args: any[]) => any>>> {
+  ): Promise<
+    (code: string, id: string, envName?: string) => Promise<ReturnType<(...args: any[]) => any>>
+  > {
     // Create tmp project with a fake package in node_modules.
     // The package name must be in DEFAULT_OPTIMIZE_PACKAGES (or configured via
     // next.config.js) for the plugin's buildStart to include it.
@@ -662,9 +683,9 @@ describe("vinext:optimize-imports transform", () => {
     if (buildStartHook) await buildStartHook.call(plugin);
 
     const transform = unwrapHook(plugin.transform)!;
-    // Return a caller that fakes the environment context as RSC (server)
-    return async (code: string, id: string) =>
-      await (transform as any).call({ ...plugin, environment: { name: "rsc" } }, code, id);
+    // Return a caller that fakes the environment context, RSC by default
+    return async (code: string, id: string, envName = "rsc") =>
+      await (transform as any).call({ ...plugin, environment: { name: envName } }, code, id);
   }
 
   afterEach(() => {
@@ -806,6 +827,78 @@ describe("vinext:optimize-imports transform", () => {
     expect(importLines[0]).toContain(expected);
   });
 
+  it('stops at a "use client" entry in RSC but not in SSR', async () => {
+    // antd is in DEFAULT_OPTIMIZE_PACKAGES, and its entry starts with "use client".
+    const call = await setupTransform("antd", `"use client";\nexport { Button } from "./button";`);
+    const pkgDir = path.posix.join(tmpDir, "node_modules", "antd");
+    const code = `import { Button } from "antd";`;
+    const rscResult = await call(code, "/app/page.tsx", "rsc");
+    expect(rscResult!.code).toContain(
+      `import { Button } from ${JSON.stringify(path.posix.join(pkgDir, "index.js"))}`,
+    );
+
+    const ssrResult = await call(code, "/app/page.tsx", "ssr");
+    expect(ssrResult!.code).toContain(
+      `import { Button } from ${JSON.stringify(path.posix.join(pkgDir, "button"))}`,
+    );
+  });
+
+  it("only registers the packages this environment imports for resolveId", async () => {
+    tmpDir = toSlash(
+      fs.realpathSync(fs.mkdtempSync(path.join(os.tmpdir(), "vinext-optimize-test-"))),
+    );
+    fs.writeFileSync(
+      path.join(tmpDir, "package.json"),
+      JSON.stringify({ name: "test-app", type: "module" }),
+    );
+    const pkgDir = path.join(tmpDir, "node_modules", "antd");
+    fs.mkdirSync(pkgDir, { recursive: true });
+    fs.writeFileSync(
+      path.join(pkgDir, "package.json"),
+      JSON.stringify({ name: "antd", type: "module", main: "./index.js" }),
+    );
+    fs.writeFileSync(
+      path.join(pkgDir, "index.js"),
+      `"use client";\nexport { Slot } from "@radix-ui/react-slot";`,
+    );
+
+    const plugin = createOptimizeImportsPlugin(
+      () => undefined,
+      () => tmpDir,
+    ) as Plugin;
+    const buildStartHook = unwrapHook((plugin as any).buildStart);
+    if (buildStartHook) await buildStartHook.call(plugin);
+    const transform = unwrapHook(plugin.transform)!;
+    const resolveId = unwrapHook(plugin.resolveId)!;
+    const rsc = { ...plugin, environment: { name: "rsc" }, resolve: vi.fn() };
+    const ssr = { ...plugin, environment: { name: "ssr" }, resolve: vi.fn() };
+
+    // SSR imports Slot from @radix-ui/react-slot, but RSC imports it from the
+    // "use client" entry, whichever environment transforms first.
+    for (const context of [ssr, rsc]) {
+      await (transform as any).call(context, `import { Slot } from "antd";`, "/app/page.tsx");
+      await (resolveId as any).call(context, "@radix-ui/react-slot", "/app/other.tsx");
+    }
+    expect(ssr.resolve).toHaveBeenCalledOnce();
+    expect(rsc.resolve).not.toHaveBeenCalled();
+  });
+
+  it('stops at "use server" modules in SSR', async () => {
+    const call = await setupTransform("antd", `export * from "./actions.js";`);
+    const pkgDir = path.posix.join(tmpDir, "node_modules", "antd");
+    fs.writeFileSync(
+      path.join(pkgDir, "actions.js"),
+      `"use server";\nexport { submit } from "./submit.js";`,
+    );
+    const code = `import { submit } from "antd";`;
+    for (const envName of ["rsc", "ssr"]) {
+      const result = await call(code, "/app/page.tsx", envName);
+      expect(result!.code).toContain(
+        `import { submit } from ${JSON.stringify(path.posix.join(pkgDir, "actions.js"))}`,
+      );
+    }
+  });
+
   it("produces separate statements for namespace and named imports from the same source", async () => {
     // lodash-es is in DEFAULT_OPTIMIZE_PACKAGES.
     // The barrel exports both a namespace re-export and a named re-export pointing at
@@ -1158,7 +1251,8 @@ describe("vinext:optimize-imports subpath imports", () => {
     return { call, racDir, nestedStately, resolveCalls };
   }
 
-  const heroToastQueue = `${"/app"}/node_modules/@heroui/react/dist/components/toast/toast-queue.js?v=abc`;
+  const heroToastQueue =
+    "/app/node_modules/@heroui/react/dist/components/toast/toast-queue.js?v=abc";
 
   it("optimizes react-aria-components subpaths by default", () => {
     expect(SUBPATH_OPTIMIZE_PACKAGES).toContain("react-aria-components");