diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index e2f3f0751f..f3070315f6 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -6167,6 +6167,26 @@ function wp_is_uuid( $uuid, $version = null ) {
 	return (bool) preg_match( $regex, $uuid );
 }
 
+/**
+ * Get unique ID.
+ *
+ * This is a PHP implementation of Underscore's uniqueId method. A static variable
+ * contains an integer that is incremented with each call. This number is returned
+ * with the optional prefix. As such the returned value is not universally unique,
+ * but it is unique across the life of the PHP process.
+ *
+ * @since 4.9.9
+ *
+ * @staticvar int $id_counter
+ *
+ * @param string $prefix Prefix for the returned ID.
+ * @return string Unique ID.
+ */
+function wp_unique_id( $prefix = '' ) {
+	static $id_counter = 0;
+	return $prefix . (string) ++$id_counter;
+}
+
 /**
  * Get last changed date for the specified cache group.
  *
diff --git a/tests/phpunit/tests/functions.php b/tests/phpunit/tests/functions.php
index d6d5d066e0..2557f1f92a 100644
--- a/tests/phpunit/tests/functions.php
+++ b/tests/phpunit/tests/functions.php
@@ -1117,6 +1117,34 @@ class Tests_Functions extends WP_UnitTestCase {
 		}
 	}
 
+	/**
+	 * Tests wp_unique_id().
+	 *
+	 * @covers ::wp_unique_id
+	 * @ticket 44883
+	 */
+	function test_wp_unique_id() {
+
+		// Test without prefix.
+		$ids = array();
+		for ( $i = 0; $i < 20; $i += 1 ) {
+			$id = wp_unique_id();
+			$this->assertInternalType( 'string', $id );
+			$this->assertTrue( is_numeric( $id ) );
+			$ids[] = $id;
+		}
+		$this->assertEquals( $ids, array_unique( $ids ) );
+
+		// Test with prefix.
+		$ids = array();
+		for ( $i = 0; $i < 20; $i += 1 ) {
+			$id = wp_unique_id( 'foo-' );
+			$this->assertRegExp( '/^foo-\d+$/', $id );
+			$ids[] = $id;
+		}
+		$this->assertEquals( $ids, array_unique( $ids ) );
+	}
+
 	/**
 	 * @ticket 40017
 	 * @dataProvider _wp_get_image_mime