diff --git a/src/Install/GuidelineComposer.php b/src/Install/GuidelineComposer.php
index 2a957af1..5e5edee2 100644
--- a/src/Install/GuidelineComposer.php
+++ b/src/Install/GuidelineComposer.php
@@ -273,7 +273,7 @@ protected function renderContent(string $content, string $path): string
      */
     protected function guideline(string $path, bool $thirdParty = false): array
     {
-        $path = $this->guidelinePath($path);
+        $path = $this->guidelinePath($path, $thirdParty);
         if (is_null($path)) {
             return [
                 'content' => '',
@@ -349,7 +349,7 @@ private function prependGuidelinePath(string $path, string $basePath): string
         return str_replace('/', DIRECTORY_SEPARATOR, $basePath.$path);
     }
 
-    protected function guidelinePath(string $path): ?string
+    protected function guidelinePath(string $path, bool $thirdParty = false): ?string
     {
         // Relative path, prepend our package path to it
         if (! file_exists($path)) {
@@ -366,6 +366,27 @@ protected function guidelinePath(string $path): ?string
             return $path;
         }
 
+        // Check if this is a third-party package guideline from vendor directory
+        if ($thirdParty) {
+            $vendorPos = strpos($path, DIRECTORY_SEPARATOR.'vendor'.DIRECTORY_SEPARATOR);
+            $afterVendor = substr($path, $vendorPos + strlen(DIRECTORY_SEPARATOR.'vendor'.DIRECTORY_SEPARATOR));
+
+            // Remove common guideline directory patterns
+            $relativePath = str_replace(
+                DIRECTORY_SEPARATOR.implode(DIRECTORY_SEPARATOR, [
+                    'resources',
+                    'boost',
+                    'guidelines',
+                ]).DIRECTORY_SEPARATOR,
+                DIRECTORY_SEPARATOR,
+                $afterVendor
+            );
+
+            $customPath = $this->prependUserGuidelinePath($relativePath);
+
+            return file_exists($customPath) ? $customPath : $path;
+        }
+
         // The path is not a custom guideline, check if the user has an override for this
         $basePath = realpath(__DIR__.'/../../');
         $relativePath = ltrim(str_replace([$basePath, '.ai'.DIRECTORY_SEPARATOR, '.ai/'], '', $path), '/\\');
diff --git a/tests/Feature/Install/GuidelineComposerTest.php b/tests/Feature/Install/GuidelineComposerTest.php
index dfb2399b..b690a311 100644
--- a/tests/Feature/Install/GuidelineComposerTest.php
+++ b/tests/Feature/Install/GuidelineComposerTest.php
@@ -588,3 +588,109 @@
         ->not->toContain('Wayfinder + Inertia')
         ->not->toContain('Wayfinder Form Component');
 });
+
+test('loads third-party guidelines from vendor directory when no override exists', function (): void {
+    $packages = new PackageCollection([
+        new Package(Packages::LARAVEL, 'laravel/framework', '11.0.0'),
+    ]);
+
+    $this->roster->shouldReceive('packages')->andReturn($packages);
+
+    $composer = Mockery::mock(GuidelineComposer::class, [$this->roster, $this->herd])->makePartial();
+    $composer
+        ->shouldReceive('customGuidelinePath')
+        ->andReturnUsing(fn ($path = ''): string => realpath(testDirectory('fixtures/.ai/guidelines')).DIRECTORY_SEPARATOR.ltrim((string) $path, '/\\'));
+
+    // Simulate loading a vendor guideline without an override
+    $vendorPath = realpath(testDirectory('fixtures/vendor/spatie/laravel-permission/resources/boost/guidelines/core.blade.php'));
+    $reflection = new ReflectionClass($composer);
+    $method = $reflection->getMethod('guideline');
+    $method->setAccessible(true);
+    $result = $method->invoke($composer, $vendorPath, true);
+
+    expect($result)
+        ->toBeArray()
+        ->toHaveKey('content')
+        ->toHaveKey('path')
+        ->and($result['content'])
+        ->toContain('This is a third-party guideline without an override')
+        ->toContain('Always use Spatie\'s permission system for authorization')
+        ->and($result['third_party'])
+        ->toBeTrue()
+        ->and($result['path'])
+        ->toBe($vendorPath); // Should use vendor path since no override exists
+});
+
+test('overrides third-party guidelines from vendor directory with custom guidelines', function (): void {
+    $packages = new PackageCollection([
+        new Package(Packages::LARAVEL, 'laravel/framework', '11.0.0'),
+    ]);
+
+    $this->roster->shouldReceive('packages')->andReturn($packages);
+
+    $composer = Mockery::mock(GuidelineComposer::class, [$this->roster, $this->herd])->makePartial();
+    $composer
+        ->shouldReceive('customGuidelinePath')
+        ->andReturnUsing(fn ($path = ''): string => realpath(testDirectory('fixtures/.ai/guidelines')).DIRECTORY_SEPARATOR.ltrim((string) $path, '/\\'));
+
+    // Simulate loading a vendor guideline that has an override
+    $vendorPath = realpath(testDirectory('fixtures/vendor/laravel/fortify/resources/boost/guidelines/core.blade.php'));
+    $reflection = new ReflectionClass($composer);
+    $method = $reflection->getMethod('guideline');
+    $method->setAccessible(true);
+    $result = $method->invoke($composer, $vendorPath, true);
+
+    // Normalize paths for cross-platform comparison
+    $expectedOverridePath = str_replace('/', DIRECTORY_SEPARATOR, '.ai/guidelines/laravel/fortify/core.blade.php');
+
+    expect($result)
+        ->toBeArray()
+        ->toHaveKey('content')
+        ->toHaveKey('path')
+        ->and($result['content'])
+        ->toContain('This is a custom override for Laravel Fortify guidelines')
+        ->toContain('Never use two-factor authentication in development')
+        ->not->toContain('This is the original third-party guideline from the vendor directory')
+        ->and($result['third_party'])
+        ->toBeTrue()
+        ->and($result['path'])
+        ->toContain($expectedOverridePath) // Should use override path
+        ->not->toContain('vendor');
+});
+
+test('guidelinePath correctly resolves vendor package paths to override locations', function (): void {
+    $packages = new PackageCollection([
+        new Package(Packages::LARAVEL, 'laravel/framework', '11.0.0'),
+    ]);
+
+    $this->roster->shouldReceive('packages')->andReturn($packages);
+
+    $composer = Mockery::mock(GuidelineComposer::class, [$this->roster, $this->herd])->makePartial();
+    $composer
+        ->shouldReceive('customGuidelinePath')
+        ->andReturnUsing(fn ($path = ''): string => realpath(testDirectory('fixtures/.ai/guidelines')).DIRECTORY_SEPARATOR.ltrim((string) $path, '/\\'));
+
+    $reflection = new ReflectionClass($composer);
+    $method = $reflection->getMethod('guidelinePath');
+    $method->setAccessible(true);
+
+    // Test with override present
+    $vendorPathWithOverride = realpath(testDirectory('fixtures/vendor/laravel/fortify/resources/boost/guidelines/core.blade.php'));
+    $resolvedPath = $method->invoke($composer, $vendorPathWithOverride, true);
+
+    // Normalize paths for cross-platform comparison
+    $expectedOverridePath = str_replace('/', DIRECTORY_SEPARATOR, '.ai/guidelines/laravel/fortify/core.blade.php');
+    $expectedVendorPath = str_replace('/', DIRECTORY_SEPARATOR, 'vendor/spatie/laravel-permission');
+
+    expect($resolvedPath)
+        ->toContain($expectedOverridePath)
+        ->not->toContain('vendor');
+
+    // Test without override
+    $vendorPathWithoutOverride = realpath(testDirectory('fixtures/vendor/spatie/laravel-permission/resources/boost/guidelines/core.blade.php'));
+    $resolvedPath = $method->invoke($composer, $vendorPathWithoutOverride, true);
+
+    expect($resolvedPath)
+        ->toContain($expectedVendorPath)
+        ->toBe($vendorPathWithoutOverride);
+});
diff --git a/tests/fixtures/.ai/guidelines/laravel/fortify/core.blade.php b/tests/fixtures/.ai/guidelines/laravel/fortify/core.blade.php
new file mode 100644
index 00000000..a1f96f83
--- /dev/null
+++ b/tests/fixtures/.ai/guidelines/laravel/fortify/core.blade.php
@@ -0,0 +1,5 @@
+# Laravel Fortify (Custom Override)
+
+This is a custom override for Laravel Fortify guidelines.
+
+Never use two-factor authentication in development.
diff --git a/tests/fixtures/vendor/laravel/fortify/resources/boost/guidelines/core.blade.php b/tests/fixtures/vendor/laravel/fortify/resources/boost/guidelines/core.blade.php
new file mode 100644
index 00000000..a6c0b81a
--- /dev/null
+++ b/tests/fixtures/vendor/laravel/fortify/resources/boost/guidelines/core.blade.php
@@ -0,0 +1,5 @@
+# Laravel Fortify (Vendor Version)
+
+This is the original third-party guideline from the vendor directory.
+
+Use Fortify's two-factor authentication features.
diff --git a/tests/fixtures/vendor/spatie/laravel-permission/resources/boost/guidelines/core.blade.php b/tests/fixtures/vendor/spatie/laravel-permission/resources/boost/guidelines/core.blade.php
new file mode 100644
index 00000000..d2f7460e
--- /dev/null
+++ b/tests/fixtures/vendor/spatie/laravel-permission/resources/boost/guidelines/core.blade.php
@@ -0,0 +1,5 @@
+# Spatie Laravel Permission
+
+This is a third-party guideline without an override.
+
+Always use Spatie's permission system for authorization.