diff --git a/includes/Traits/License_Utils.php b/includes/Traits/License_Utils.php
index 4a3db8d21..8ccbf3c14 100644
--- a/includes/Traits/License_Utils.php
+++ b/includes/Traits/License_Utils.php
@@ -82,7 +82,7 @@ protected function is_license_valid_identifier( $license ) {
 	 * @return bool true if the license is GPL compatible, otherwise false.
 	 */
 	protected function is_license_gpl_compatible( $license ) {
-		$match = preg_match( '/GPL|GNU|MIT|FreeBSD|New BSD|BSD-3-Clause|BSD 3 Clause|OpenLDAP|Expat|Apache|MPL20/im', $license );
+		$match = preg_match( '/GPL|GNU|MIT|FreeBSD|New BSD|BSD-3-Clause|BSD 3 Clause|OpenLDAP|Expat|Apache|MPL20|ISC/im', $license );
 
 		return ( false === $match || 0 === $match ) ? false : true;
 	}
diff --git a/tests/phpunit/tests/Traits/License_Utils_Tests.php b/tests/phpunit/tests/Traits/License_Utils_Tests.php
index 1fb256639..3a01809d6 100644
--- a/tests/phpunit/tests/Traits/License_Utils_Tests.php
+++ b/tests/phpunit/tests/Traits/License_Utils_Tests.php
@@ -104,6 +104,7 @@ public function data_license_gpl_compatibility() {
 			array( 'BSD 3 Clause', true ),
 			array( 'OpenLDAP', true ),
 			array( 'Expat', true ),
+			array( 'ISC', true ),
 
 			array( 'EPL', false ),
 			array( 'EUPL', false ),