diff --git a/lib/compiler/plugins/plugin-metadata-generator.ts b/lib/compiler/plugins/plugin-metadata-generator.ts
index 156f843da..7b5c4684a 100644
--- a/lib/compiler/plugins/plugin-metadata-generator.ts
+++ b/lib/compiler/plugins/plugin-metadata-generator.ts
@@ -8,6 +8,127 @@ import { TypeCheckerHost } from '../swc/type-checker-host';
 import { TypeScriptBinaryLoader } from '../typescript-loader';
 import { PluginMetadataPrinter } from './plugin-metadata-printer';
 
+/**
+ * Returns `true` when the consuming project uses an ESM-style module
+ * resolution strategy (`node16` / `nodenext`). Under those resolution
+ * modes, dynamic `import()` specifiers MUST include the file extension
+ * (typically `.js`) for the runtime resolver to find the module. Without
+ * the extension, executing the generated metadata file fails with
+ * `ERR_MODULE_NOT_FOUND`, and TypeScript reports a diagnostic.
+ */
+export function requiresExplicitImportExtensions(
+  options: ts.CompilerOptions,
+  tsBinary: typeof ts,
+): boolean {
+  const moduleResolution = options.moduleResolution;
+  return (
+    moduleResolution === tsBinary.ModuleResolutionKind.Node16 ||
+    moduleResolution === tsBinary.ModuleResolutionKind.NodeNext
+  );
+}
+
+const RELATIVE_PATH_RE = /^\.\.?\//;
+// Any common JS/TS-style extension that the user could have authored or
+// that our rewrite would have already produced. Prevents double-appending.
+const HAS_KNOWN_EXTENSION_RE = /\.(m?js|c?js|m?ts|c?ts|json|node)$/i;
+
+/**
+ * Returns the same import path with `.js` appended when (and only when)
+ * the path is relative and does not already end in a recognized
+ * extension. Bare specifiers (e.g. `@nestjs/common`) and absolute paths
+ * are returned unchanged because the caller's resolver handles them.
+ */
+export function appendJsExtensionIfMissing(importPath: string): string {
+  if (!RELATIVE_PATH_RE.test(importPath)) {
+    return importPath;
+  }
+  if (HAS_KNOWN_EXTENSION_RE.test(importPath)) {
+    return importPath;
+  }
+  return `${importPath}.js`;
+}
+
+/**
+ * Rewrites a single `await import("...")`-style string by appending the
+ * `.js` extension to the inner specifier when it is a relative path
+ * without an extension. Used to patch the visitor-supplied `typeImports`
+ * map values.
+ */
+export function rewriteAsyncImportString(target: string): string {
+  return target.replace(
+    /import\((['"])((?:\\\1|(?!\1).)*)\1\)/g,
+    (match, quote, specifier) =>
+      `import(${quote}${appendJsExtensionIfMissing(specifier)}${quote})`,
+  );
+}
+
+/**
+ * Walks the given `ts.CallExpression` tree and rewrites every dynamic
+ * `import("...")` whose specifier is a relative path missing an
+ * extension. Returns a new node when changes are required, or the input
+ * node unchanged otherwise.
+ */
+export function rewriteImportExpressionForNodeNext(
+  expression: ts.CallExpression,
+  tsBinary: typeof ts,
+): ts.CallExpression {
+  const visit = (node: ts.Node): ts.Node => {
+    if (
+      tsBinary.isCallExpression(node) &&
+      node.expression.kind === tsBinary.SyntaxKind.ImportKeyword &&
+      node.arguments.length > 0 &&
+      tsBinary.isStringLiteralLike(node.arguments[0])
+    ) {
+      const original = (node.arguments[0] as ts.StringLiteralLike).text;
+      const rewritten = appendJsExtensionIfMissing(original);
+      if (rewritten !== original) {
+        const updatedArgs = [
+          tsBinary.factory.createStringLiteral(rewritten),
+          ...node.arguments.slice(1),
+        ];
+        return tsBinary.factory.updateCallExpression(
+          node,
+          node.expression,
+          node.typeArguments,
+          updatedArgs,
+        );
+      }
+    }
+    return tsBinary.visitEachChild(node, visit, undefined as any);
+  };
+  return visit(expression) as ts.CallExpression;
+}
+
+/**
+ * Recursively walks the collected plugin metadata, rewriting every
+ * dynamic `import("./relative")` call expression to include the `.js`
+ * extension required by node16 / nodenext module resolution.
+ */
+export function rewriteCollectedMetadataForNodeNext(
+  metadata: Record<
+    string,
+    Record<string, Array<[ts.CallExpression, DeepPluginMeta]>>
+  >,
+  tsBinary: typeof ts,
+): void {
+  for (const visitorKey of Object.keys(metadata)) {
+    const sections = metadata[visitorKey];
+    for (const sectionKey of Object.keys(sections)) {
+      const tuples = sections[sectionKey];
+      if (!Array.isArray(tuples)) {
+        continue;
+      }
+      for (let i = 0; i < tuples.length; i++) {
+        const [importExpr, meta] = tuples[i];
+        tuples[i] = [
+          rewriteImportExpressionForNodeNext(importExpr, tsBinary),
+          meta,
+        ];
+      }
+    }
+  }
+}
+
 export interface PluginMetadataGenerateOptions {
   /**
    * The visitors to use to generate the metadata.
@@ -150,6 +271,26 @@ export class PluginMetadataGenerator {
         ...visitor.typeImports,
       };
     });
+
+    // Under `node16` / `nodenext` module resolution, dynamic `import()`
+    // specifiers must include explicit file extensions. The visitors emit
+    // bare relative specifiers (e.g. `import("./hello.dto")`), which are
+    // valid under classic / node10 resolution but break compilation and
+    // runtime under nodenext. When the consuming project uses an ESM-style
+    // resolver, rewrite both the metadata import call expressions and the
+    // typeImports map values to include the `.js` extension. See #3364.
+    if (
+      requiresExplicitImportExtensions(
+        programRef.getCompilerOptions(),
+        this.tsBinary,
+      )
+    ) {
+      rewriteCollectedMetadataForNodeNext(collectedMetadata, this.tsBinary);
+      for (const key of Object.keys(typeImports)) {
+        typeImports[key] = rewriteAsyncImportString(typeImports[key]);
+      }
+    }
+
     this.pluginMetadataPrinter.print(
       collectedMetadata,
       typeImports,
diff --git a/test/lib/compiler/plugins/plugin-metadata-generator.spec.ts b/test/lib/compiler/plugins/plugin-metadata-generator.spec.ts
new file mode 100644
index 000000000..6857accb2
--- /dev/null
+++ b/test/lib/compiler/plugins/plugin-metadata-generator.spec.ts
@@ -0,0 +1,203 @@
+import * as ts from 'typescript';
+import {
+  appendJsExtensionIfMissing,
+  requiresExplicitImportExtensions,
+  rewriteAsyncImportString,
+  rewriteCollectedMetadataForNodeNext,
+  rewriteImportExpressionForNodeNext,
+} from '../../../../lib/compiler/plugins/plugin-metadata-generator';
+
+function createImportCall(specifier: string): ts.CallExpression {
+  return ts.factory.createCallExpression(
+    ts.factory.createToken(ts.SyntaxKind.ImportKeyword) as unknown as ts.Expression,
+    undefined,
+    [ts.factory.createStringLiteral(specifier)],
+  );
+}
+
+function printNode(node: ts.Node): string {
+  const printer = ts.createPrinter({ newLine: ts.NewLineKind.LineFeed });
+  const sourceFile = ts.createSourceFile(
+    'tmp.ts',
+    '',
+    ts.ScriptTarget.Latest,
+    false,
+    ts.ScriptKind.TS,
+  );
+  return printer.printNode(ts.EmitHint.Unspecified, node, sourceFile);
+}
+
+describe('PluginMetadataGenerator (#3364: nodenext import extensions)', () => {
+  describe('requiresExplicitImportExtensions', () => {
+    it('returns true for Node16 module resolution', () => {
+      expect(
+        requiresExplicitImportExtensions(
+          { moduleResolution: ts.ModuleResolutionKind.Node16 },
+          ts,
+        ),
+      ).toBe(true);
+    });
+
+    it('returns true for NodeNext module resolution', () => {
+      expect(
+        requiresExplicitImportExtensions(
+          { moduleResolution: ts.ModuleResolutionKind.NodeNext },
+          ts,
+        ),
+      ).toBe(true);
+    });
+
+    it('returns false for Node10 / classic module resolution', () => {
+      expect(
+        requiresExplicitImportExtensions(
+          { moduleResolution: ts.ModuleResolutionKind.Node10 },
+          ts,
+        ),
+      ).toBe(false);
+      expect(
+        requiresExplicitImportExtensions(
+          { moduleResolution: ts.ModuleResolutionKind.Classic },
+          ts,
+        ),
+      ).toBe(false);
+    });
+
+    it('returns false when moduleResolution is undefined', () => {
+      expect(requiresExplicitImportExtensions({}, ts)).toBe(false);
+    });
+
+    it('returns false for the Bundler resolver (extensions not required)', () => {
+      expect(
+        requiresExplicitImportExtensions(
+          { moduleResolution: ts.ModuleResolutionKind.Bundler },
+          ts,
+        ),
+      ).toBe(false);
+    });
+  });
+
+  describe('appendJsExtensionIfMissing', () => {
+    it('appends `.js` to relative paths without an extension', () => {
+      expect(appendJsExtensionIfMissing('./hello.dto')).toBe('./hello.dto.js');
+      expect(appendJsExtensionIfMissing('../shared/user')).toBe(
+        '../shared/user.js',
+      );
+    });
+
+    it('leaves bare specifiers unchanged', () => {
+      expect(appendJsExtensionIfMissing('@nestjs/common')).toBe(
+        '@nestjs/common',
+      );
+      expect(appendJsExtensionIfMissing('rxjs')).toBe('rxjs');
+    });
+
+    it('does not double-append when an extension is already present', () => {
+      expect(appendJsExtensionIfMissing('./hello.dto.js')).toBe(
+        './hello.dto.js',
+      );
+      expect(appendJsExtensionIfMissing('./hello.dto.mjs')).toBe(
+        './hello.dto.mjs',
+      );
+      expect(appendJsExtensionIfMissing('./hello.dto.cjs')).toBe(
+        './hello.dto.cjs',
+      );
+      expect(appendJsExtensionIfMissing('./data.json')).toBe('./data.json');
+    });
+
+    it('leaves absolute paths unchanged', () => {
+      expect(appendJsExtensionIfMissing('/usr/lib/foo')).toBe('/usr/lib/foo');
+    });
+  });
+
+  describe('rewriteAsyncImportString', () => {
+    it('rewrites a single dynamic import inside an `await import(...)` string', () => {
+      expect(rewriteAsyncImportString('await import("./hello.dto")')).toBe(
+        'await import("./hello.dto.js")',
+      );
+    });
+
+    it('rewrites the dynamic import in a `(await import(...)).Foo` expression', () => {
+      expect(
+        rewriteAsyncImportString('(await import("./user.dto")).UserDto'),
+      ).toBe('(await import("./user.dto.js")).UserDto');
+    });
+
+    it('leaves bare-specifier dynamic imports alone', () => {
+      expect(
+        rewriteAsyncImportString('await import("@nestjs/common")'),
+      ).toBe('await import("@nestjs/common")');
+    });
+
+    it('does not re-append the extension on a previously-rewritten string', () => {
+      const once = rewriteAsyncImportString('await import("./hello.dto")');
+      const twice = rewriteAsyncImportString(once);
+      expect(twice).toBe('await import("./hello.dto.js")');
+    });
+
+    it('handles single-quoted import specifiers', () => {
+      expect(rewriteAsyncImportString("await import('./foo')")).toBe(
+        "await import('./foo.js')",
+      );
+    });
+  });
+
+  describe('rewriteImportExpressionForNodeNext', () => {
+    it('rewrites a top-level `import("./relative")` call expression', () => {
+      const call = createImportCall('./hello.dto');
+      const rewritten = rewriteImportExpressionForNodeNext(call, ts);
+      expect(printNode(rewritten)).toBe('import("./hello.dto.js")');
+    });
+
+    it('leaves bare-specifier `import("rxjs")` calls unchanged', () => {
+      const call = createImportCall('rxjs');
+      const rewritten = rewriteImportExpressionForNodeNext(call, ts);
+      expect(printNode(rewritten)).toBe('import("rxjs")');
+    });
+
+    it('does not modify a call that already includes a `.js` extension', () => {
+      const call = createImportCall('./foo.js');
+      const rewritten = rewriteImportExpressionForNodeNext(call, ts);
+      expect(printNode(rewritten)).toBe('import("./foo.js")');
+    });
+  });
+
+  describe('rewriteCollectedMetadataForNodeNext', () => {
+    it('rewrites import call expressions across the entire metadata tree', () => {
+      const fakeObjectLiteral = ts.factory.createObjectLiteralExpression([]);
+      const metadata: Record<
+        string,
+        Record<
+          string,
+          Array<[ts.CallExpression, Record<string, never>]>
+        >
+      > = {
+        '@nestjs/swagger': {
+          models: [
+            [createImportCall('./hello.dto'), {}],
+            [createImportCall('../shared/user.dto'), {}],
+            [createImportCall('@nestjs/common'), {}],
+          ],
+          controllers: [[createImportCall('./app.controller'), {}]],
+        },
+      };
+
+      // Use the fake object literal somewhere so TS doesn't drop it; not used
+      // by the rewriter but mirrors the real-world metadata shape.
+      void fakeObjectLiteral;
+
+      rewriteCollectedMetadataForNodeNext(metadata as any, ts);
+
+      const printed = metadata['@nestjs/swagger'].models.map(([imp]) =>
+        printNode(imp),
+      );
+      expect(printed).toEqual([
+        'import("./hello.dto.js")',
+        'import("../shared/user.dto.js")',
+        'import("@nestjs/common")',
+      ]);
+      expect(
+        printNode(metadata['@nestjs/swagger'].controllers[0][0]),
+      ).toBe('import("./app.controller.js")');
+    });
+  });
+});