diff --git a/src/wp-includes/option.php b/src/wp-includes/option.php
index c813695030..4df0b81458 100644
--- a/src/wp-includes/option.php
+++ b/src/wp-includes/option.php
@@ -2903,7 +2903,10 @@ function unregister_setting( $option_group, $option_name, $deprecated = '' ) {
 		$option_group = 'reading';
 	}
 
-	$pos = array_search( $option_name, (array) $new_allowed_options[ $option_group ], true );
+	$pos = false;
+	if ( isset( $new_allowed_options[ $option_group ] ) ) {
+		$pos = array_search( $option_name, (array) $new_allowed_options[ $option_group ], true );
+	}
 
 	if ( false !== $pos ) {
 		unset( $new_allowed_options[ $option_group ][ $pos ] );
diff --git a/tests/phpunit/tests/option/registration.php b/tests/phpunit/tests/option/registration.php
index 04991e4a33..9b0e418c91 100644
--- a/tests/phpunit/tests/option/registration.php
+++ b/tests/phpunit/tests/option/registration.php
@@ -149,4 +149,18 @@ class Tests_Option_Registration extends WP_UnitTestCase {
 
 		$this->assertFalse( has_filter( 'default_option_test_default', 'filter_default_option' ) );
 	}
+
+	/**
+	 * The test passes if a Notice | Warning | Error is not raised. Thus. the absence of a Notice | Warning | Error
+	 * is an indicator the fix in the ticket resolves the issue.
+	 *
+	 * @ticket 57674
+	 *
+	 * @covers ::unregister_setting
+	 */
+	public function test_unregister_invalid_setting_does_not_raise_php_notice_warning_or_error() {
+		$setting = uniqid();
+		unregister_setting( $setting, $setting );
+		$this->assertFalse( has_filter( 'default_option_' . $setting, 'filter_default_option' ) );
+	}
 }