Gregory's Girl had such a small budget that the actors had to supply some of their own wardrobes.
Dee Hepburn, who plays Dorothy, trained with the Partick Thistle Football Club in order to hone her football skills. A banner for the team can be seen in a scene of Gregory's bedroom.
A person in a penguin costume appears at random points during the film. Inside the suit was production manager Peter Higson's son, Christopher.
When the film was released in America, it was re-dubbed with slightly more diluted Scottish accents.