diff --git a/src/Control/Director.php b/src/Control/Director.php
index 9c9b29642..0790d0b99 100644
--- a/src/Control/Director.php
+++ b/src/Control/Director.php
@@ -944,7 +944,7 @@ class Director implements TemplateGlobalProvider
      */
     public static function is_cli()
     {
-        return php_sapi_name() === "cli";
+        return in_array(php_sapi_name(), ['cli', 'phpdbg']);
     }
 
     /**
diff --git a/tests/php/Control/DirectorTest.php b/tests/php/Control/DirectorTest.php
index e9fd2b741..3e6c58bde 100644
--- a/tests/php/Control/DirectorTest.php
+++ b/tests/php/Control/DirectorTest.php
@@ -761,4 +761,12 @@ class DirectorTest extends SapphireTest
         $this->assertEquals(2, $middleware->preCalls);
         $this->assertEquals(1, $specificMiddleware->postCalls);
     }
+
+    /**
+     * If using phpdbg it returns itself instead of "cli" from php_sapi_name()
+     */
+    public function testIsCli()
+    {
+        $this->assertTrue(Director::is_cli(), 'is_cli should be true for PHP CLI and phpdbg');
+    }
 }