diff --git src/wp-includes/customize/class-wp-customize-custom-css-setting.php src/wp-includes/customize/class-wp-customize-custom-css-setting.php
index cb0f151..ff66efe 100644
--- src/wp-includes/customize/class-wp-customize-custom-css-setting.php
+++ src/wp-includes/customize/class-wp-customize-custom-css-setting.php
@@ -192,12 +192,6 @@ final class WP_Customize_Custom_CSS_Setting extends WP_Customize_Setting {
 		}
 
 		// Ensure single quotes are equal.
-		if ( ! $this->validate_equal_characters( '\'', $css ) ) {
-			$validity->add( 'unequal_single_quotes', __( 'Your single quotes <code>\'</code> are uneven. Make sure there is a closing <code>\'</code> for every opening <code>\'</code>.' ) );
-			$imbalanced = true;
-		}
-
-		// Ensure single quotes are equal.
 		if ( ! $this->validate_equal_characters( '"', $css ) ) {
 			$validity->add( 'unequal_double_quotes', __( 'Your double quotes <code>"</code> are uneven. Make sure there is a closing <code>"</code> for every opening <code>"</code>.' ) );
 			$imbalanced = true;
diff --git tests/phpunit/tests/customize/custom-css-setting.php tests/phpunit/tests/customize/custom-css-setting.php
index 102d303..7aff1b4 100644
--- tests/phpunit/tests/customize/custom-css-setting.php
+++ tests/phpunit/tests/customize/custom-css-setting.php
@@ -364,11 +364,6 @@ class Test_WP_Customize_Custom_CSS_Setting extends WP_UnitTestCase {
 		$result = $this->setting->validate( $imbalanced_double_quotes );
 		$this->assertTrue( array_key_exists( 'unequal_double_quotes', $result->errors ) );
 
-		// Check for Imbalanced Single Quotes.
-		$imbalanced_single_quotes = $basic_css . " div.background-image { background-image: url( 'image.jpg ); } ";
-		$result = $this->setting->validate( $imbalanced_single_quotes );
-		$this->assertTrue( array_key_exists( 'unequal_single_quotes', $result->errors ) );
-
 		// Check for Unclosed Parentheses.
 		$unclosed_parentheses = $basic_css . ' div.background-image { background-image: url( "image.jpg" ; } ';
 		$result = $this->setting->validate( $unclosed_parentheses );