diff --git a/tools/@aws-cdk/node-bundle/src/api/bundle.ts b/tools/@aws-cdk/node-bundle/src/api/bundle.ts
index c438e059a8cf8..b1356ed6a6505 100644
--- a/tools/@aws-cdk/node-bundle/src/api/bundle.ts
+++ b/tools/@aws-cdk/node-bundle/src/api/bundle.ts
@@ -224,9 +224,12 @@ export class Bundle {
 
     const target = fs.mkdtempSync(path.join(os.tmpdir(), 'bundle-write-'));
 
+    // we definitely don't need these directories in the package
+    // so no need to copy them over.
+    const ignoreDirectories = ['node_modules', '.git'];
+
     // copy the entire project since we are retaining the original files.
-    // except for `node_modules` and `.git` which definitely don't belong in the package.
-    fs.copySync(this.packageDir, target, { filter: n => !n.includes('node_modules') && !n.includes('.git') });
+    fs.copySync(this.packageDir, target, { filter: n => !n.split(path.sep).some((p => ignoreDirectories.includes(p))) });
 
     // clone the original manifest since we are going to
     // to mutate it.
diff --git a/tools/@aws-cdk/node-bundle/test/api/bundle.test.ts b/tools/@aws-cdk/node-bundle/test/api/bundle.test.ts
index de7f741bc880e..3a01c349d5669 100644
--- a/tools/@aws-cdk/node-bundle/test/api/bundle.test.ts
+++ b/tools/@aws-cdk/node-bundle/test/api/bundle.test.ts
@@ -127,3 +127,31 @@ test('validate and fix', () => {
   expect(fs.existsSync(tarball)).toBeTruthy();
 
 });
+
+test('write ignores only .git and node_modules directories', () => {
+
+  const pkg = Package.create({ name: 'consumer', licenses: ['Apache-2.0'] });
+  pkg.addDependency({ name: 'dep1', licenses: ['MIT'] });
+  pkg.addDependency({ name: 'dep2', licenses: ['Apache-2.0'] });
+
+  pkg.write();
+  pkg.install();
+
+  const bundle = new Bundle({
+    packageDir: pkg.dir,
+    entryPoints: [pkg.entrypoint],
+    allowedLicenses: ['Apache-2.0', 'MIT'],
+  });
+
+  // add a gitignore file to the package - it should be included
+  fs.writeFileSync(path.join(pkg.dir, '.gitignore'), 'something');
+
+  // add a silly node_modules_file to the package - it should be included
+  fs.writeFileSync(path.join(pkg.dir, 'node_modules_file'), 'something');
+
+  const bundleDir = bundle.write();
+
+  expect(fs.existsSync(path.join(bundleDir, '.gitignore'))).toBeTruthy();
+  expect(fs.existsSync(path.join(bundleDir, 'node_modules_file'))).toBeTruthy();
+
+});
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