The teenager needed hospital treatment after being bitten on her arm and leg by the German Shepherd-type dog in Charlestown Road, Glossop, at about 7.30pm on Thursday night.
A Derbyshire Police spokeswoman confirmed the animal belonged to a dog handler with Greater Manchester Police and had escaped from its kennel at the officer’s home address in the town.
The girl required hospital treatment but her injuries are not thought to be life-threatening, the spokeswoman added.
Two men who tried to fight the dog off the girl were also injured.
An 18-year-old was bitten on his arm, while a 48-year-old suffered scratches and had his shirt ripped during the incident.
The attack came half an hour after a man reported a separate attack by the dog in Pennine Road in the town at 7pm. The dog was finally captured by its handler in King Street at about 9.50pm.
Derbyshire Police have launched an inquiry with Greater Manchester Police.