Casteels is a surname. Notable people with the surname include:
Alexander Casteels the Elder (-1733), Flemish painter Alexander Casteels the Younger (fl 1687–1716), Flemish painter Eddy Casteels (born 1960), Belgian basketball coach Gonzales Franciscus Casteels (?– after 1709), Flemish painter Koen Casteels (born 1992), Belgian football player Peter Frans Casteels (fl. 1673–1700), Flemish painter Pauwels Casteels (– after 1677), Flemish painter Pieter Casteels II (fl. 1673–1701), Flemish painter Pieter Casteels III (1684–1749), Flemish painter
See also Casteel (surname)