Family name Ислер (Isler 
, Ислер 
) , all over the world, is quite a common surname. The cognomen Ислер is characteristic of Switzerland, where it is quite a common surname, North Macedonia, where it is quite a rare surname, and France, where it is a rare surname. Measured by absolute frequency, it is the most numerous in Switzerland, the United States, and Germany. Much less frequently, Ислер is the forename as well as the last name.