Koy is a given name and surname. Notable people with the name include:
Given name Koy Banal, Filipino basketball coach Koy Detmer (born 1973), American football player
Surname Ernie Koy (1909–2007), American baseball player Ernie Koy Jr. (born 1942), American football player Jo Koy (born 1971), American stand-up comic Ted Koy (born 1947), American football player
See also Ah Koy, surname Coy (name), given name and surname , includes a list of people with the given name and surname Koi