Family name קסטלר (Kastler 
, קסטלר 
) , all over the world, is quite a rare last name. The surname קסטלר is habitual in Austria, where it is quite a rare surname, Slovakia, and Germany, where it is a rare surname. Not in comparison with a country's population, it is commonest in Germany, the United States, and France.
| VARIANT | COUNTRY |
|---|---|
| Kastler | Germany, Austria, United States, France, Slovakia |
| קסטלר | Israel |