diff --git a/src/wp-includes/kses.php b/src/wp-includes/kses.php
index b32df1beaa973..9874cddff59e1 100644
--- a/src/wp-includes/kses.php
+++ b/src/wp-includes/kses.php
@@ -2333,12 +2333,20 @@ function safecss_filter_attr( $css, $deprecated = '' ) {
 			'margin-bottom',
 			'margin-left',
 			'margin-top',
+			'margin-block-start',
+			'margin-block-end',
+			'margin-inline-start',
+			'margin-inline-end',
 
 			'padding',
 			'padding-right',
 			'padding-bottom',
 			'padding-left',
 			'padding-top',
+			'padding-block-start',
+			'padding-block-end',
+			'padding-inline-start',
+			'padding-inline-end',
 
 			'flex',
 			'flex-basis',
@@ -2346,6 +2354,11 @@ function safecss_filter_attr( $css, $deprecated = '' ) {
 			'flex-flow',
 			'flex-grow',
 			'flex-shrink',
+			'flex-wrap',
+
+			'gap',
+			'column-gap',
+			'row-gap',
 
 			'grid-template-columns',
 			'grid-auto-columns',
diff --git a/tests/phpunit/tests/kses.php b/tests/phpunit/tests/kses.php
index e6cac09c3b77f..fc33b44bd3fe3 100644
--- a/tests/phpunit/tests/kses.php
+++ b/tests/phpunit/tests/kses.php
@@ -1033,8 +1033,8 @@ public function data_test_safecss_filter_attr() {
 			),
 			// `flex` and related attributes introduced in 5.3.
 			array(
-				'css'      => 'flex: 0 1 auto;flex-basis: 75%;flex-direction: row-reverse;flex-flow: row-reverse nowrap;flex-grow: 2;flex-shrink: 1',
-				'expected' => 'flex: 0 1 auto;flex-basis: 75%;flex-direction: row-reverse;flex-flow: row-reverse nowrap;flex-grow: 2;flex-shrink: 1',
+				'css'      => 'flex: 0 1 auto;flex-basis: 75%;flex-direction: row-reverse;flex-flow: row-reverse nowrap;flex-grow: 2;flex-shrink: 1;flex-wrap: nowrap',
+				'expected' => 'flex: 0 1 auto;flex-basis: 75%;flex-direction: row-reverse;flex-flow: row-reverse nowrap;flex-grow: 2;flex-shrink: 1;flex-wrap: nowrap',
 			),
 			// `grid` and related attributes introduced in 5.3.
 			array(
@@ -1120,6 +1120,16 @@ public function data_test_safecss_filter_attr() {
 				'css'      => 'color: rgb( 100, 100, 100, .4 )',
 				'expected' => '',
 			),
+			// Gap introduced in 6.1.
+			array(
+				'css'      => 'gap: 10px;column-gap: 5px;row-gap: 20px',
+				'expected' => 'gap: 10px;column-gap: 5px;row-gap: 20px',
+			),
+			// Margin and padding logical properties introduced in 6.1.
+			array(
+				'css'      => 'margin-block-start: 1px;margin-block-end: 2px;margin-inline-start: 3px;margin-inline-end: 4px;padding-block-start: 1px;padding-block-end: 2px;padding-inline-start: 3px;padding-inline-end: 4px',
+				'expected' => 'margin-block-start: 1px;margin-block-end: 2px;margin-inline-start: 3px;margin-inline-end: 4px;padding-block-start: 1px;padding-block-end: 2px;padding-inline-start: 3px;padding-inline-end: 4px',
+			),
 		);
 	}