Gorilla suits are full-bodied costumes resembling gorillas. Gorilla suits have been used both to represent real gorillas in film and on stage, and also as a source of humour. The gorilla suit is a popular Halloween and masquerade party costume.

In 1869, Noah Brooks' short story, "Mr. Columbus Coriander's Gorilla" appeared in Bret Harte's "Overland Monthly Magazine." The story concerned a young man employed at a menagerie dressed in a gorilla suit. It is mistakenly credited to Max Adeler.

In recent decades, the work of performers or designers have altered the mechanics and effect of gorilla suits, often using animatronics, taxidermy eyes, realistic fur, and other aides. Jim Henson utilized typical gorilla suits and never a full-bodied gorilla Muppet in several productions (like in Time Piece, The Cube, some episodes of Sesame Street, and the "Avery Schreiber" episode of The Muppet Show). The person inside the gorilla suit is often uncredited. Jim Henson's Creature Shop has contributed to this development in its own way, through work on Buddy, George of the Jungle, and MirrorMask. Many suit performers of Jim Henson's characters portrayed gorillas in other productions.

In 1963, Don Martin published National Gorilla Suit Day in a collection Don Martin Bounces Back, in which Fester Bestertester mocks the (then fictitious) concept of a National Gorilla Suit Day, and suffers a series of incredible assaults from gorillas and other creatures in gorilla and other suits.

Subsequently, Don Martin fans have celebrated National Gorilla Suit Day on January 31.[1]