McMullen is a Scottish surname. The name was derived from the nickname given to a person who was bald. Earlier Gaelic forms of the name were Mac Ghille Mhaoil and Mac Mhaolain both of these referred to a person as being a son of the tonsured or bald man. Variations of the name include MacMillan, macMullen, MacMullan, McMullin, McMillan etc. The word Mac which is used as a prefix in several Gaelic names means "son of". There are two places in America, McMullen in Alabama and McMullen County in Texas which bear this name. McMullen is seen used in McMullen & sons Ltd, which is a brewery in Hertford England. It is also the name of several people including Phil McMullen an English music critic, Matthew McMullen an American writer and Sean McMullen an Australian writer of fiction.