diff --git a/tests/php/test-class-amp-core-block-handler.php b/tests/php/test-class-amp-core-block-handler.php
index 63c5591ac5f..c54cff6bc4d 100644
--- a/tests/php/test-class-amp-core-block-handler.php
+++ b/tests/php/test-class-amp-core-block-handler.php
@@ -351,6 +351,9 @@ public function test_ampify_gallery_block( $original_block_content, $expected_bl
 		$expected = preg_replace( '/ data-id="\d+"/', '', $expected );
 		$actual   = preg_replace( '/ data-id="\d+"/', '', $actual );
 
+		// Remove `wp-block-gallery-is-layout-flex` class name injected by block editor layout styles.
+		$actual = preg_replace( '/\s*(?<= class=")?wp-block-gallery-is-layout-flex\s*/', '', $actual );
+
 		// Remove `is-layout-flex` class name injected by block editor layout styles.
 		$actual = preg_replace( '/\s*(?<= class=")?is-layout-flex\s*/', '', $actual );
 
diff --git a/tests/php/validation/test-class-amp-validation-manager.php b/tests/php/validation/test-class-amp-validation-manager.php
index aefa17489bd..97bdd2c875b 100644
--- a/tests/php/validation/test-class-amp-validation-manager.php
+++ b/tests/php/validation/test-class-amp-validation-manager.php
@@ -1393,6 +1393,9 @@ public function test_add_block_source_comments( $content, $expected, $query ) {
 
 		$rendered_block = do_blocks( AMP_Validation_Manager::add_block_source_comments( $content ) );
 
+		// Remove `wp-block-columns-is-layout-flex` class name injected by block editor layout styles.
+		$rendered_block = preg_replace( '/\s*(?<= class=")?wp-block-columns-is-layout-flex\s*/', '', $rendered_block );
+
 		// Remove `is-layout-flex` class name injected by block editor layout styles.
 		$rendered_block = preg_replace( '/\s*(?<= class=")?is-layout-flex\s*/', '', $rendered_block );