In Croatia, Šupeljak families are Serbs. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb.
Prevalence
Only a few people with faimily name Šupeljak live in Croatia today, in one household only. There were 40 of them in the middle of the past century, and their number decreased significantly. They are located in only one small Croatian place, in Padjene in Knin area (<5).