Family name Gaistruk (Gaistruk 
, Гайструк 
) , in all the world, is a rare surname. The last name Gaistruk is habitual in Ukraine, where it is a rare surname, Estonia, and Poland, where it is a very rare surname. In absolute terms, it is the most numerous in Eastern Europe, particularly Ukraine, Russia, and Poland.
| VARIANT | COUNTRY |
|---|---|
| Gaistruk | Poland, Russia, Estonia |
| Гайструк | Ukraine, Russia |