Mastelić families are Croats and they are mostly from Sinj. In the past century, relatively most of Croatian residents bearing this family name were born in Sinj and Split.
Prevalence
About 290 people with faimily name Mastelić live in Croatia today, in 110 households. There were 170 of them in the middle of the past century, and their number increased by 70 percent. They are located in 9 Croatian counties, in 11 cities and 7 other places, mostly in Brnaze (155), Split (55), Sinj (25), Zagreb (20), and in Kosute in Sinj area (20).
Outside Croatia
Family name Mastelić is present in four countries on two continents.
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 2007 in source Encyclopaedia of Croatian Surnames.