diff --git a/src/AmpUtils/Sanitizers/FacebookSanitizer.php b/src/AmpUtils/Sanitizers/FacebookSanitizer.php
index 13f5b49..8b01c4b 100644
--- a/src/AmpUtils/Sanitizers/FacebookSanitizer.php
+++ b/src/AmpUtils/Sanitizers/FacebookSanitizer.php
@@ -134,7 +134,7 @@ private function create_amp_facebook_and_replace_node( $node, $embed_type ) {
 			'height' => $node->hasAttribute( 'data-height' ) ? $node->getAttribute( 'data-height' ) : $this->args['height'],
 		];
 
-		if ( '100%' === $attributes['width'] || 'auto' === $attributes['width'] ) {
+		if ( '100%' === $attributes['width'] || 'auto' === $attributes['width'] || '' === $attributes['width'] ) {
 			$attributes['layout'] = 'fixed-height';
 			$attributes['width']  = 'auto';
 		}
diff --git a/tests/Feature/AmpSanitizerTest.php b/tests/Feature/AmpSanitizerTest.php
index bffdd31..00b0f37 100644
--- a/tests/Feature/AmpSanitizerTest.php
+++ b/tests/Feature/AmpSanitizerTest.php
@@ -89,6 +89,16 @@ public function testFbVideoAuto()
 		$this->assertEquals('<amp-facebook layout="fixed-height" width="auto" height="360" data-href="https://www.facebook.com/KOMONews/videos/225376735289463/" data-show-captions="false" data-embed-as="video"></amp-facebook>', $amp_content);
 	}
 
+	/**
+	 * @group fb_test
+	 */
+	public function testFbVideoNoWidth()
+	{
+		$amp_content = Amped::convert('<div class="fb-video" data-href="https://www.facebook.com/KOMONews/videos/225376735289463/" data-width="" data-show-captions="false"></div>');
+
+		$this->assertEquals('<amp-facebook layout="fixed-height" width="auto" height="380" data-href="https://www.facebook.com/KOMONews/videos/225376735289463/" data-show-captions="false" data-embed-as="video"></amp-facebook>', $amp_content);
+	}
+
 	/**
 	 * @group fb_test
 	 */