Ajaz Ahmad Dar (28), a lorry driver, was arrested from his native Palpora village in Handwara area of the district by a special police team, a police official said.
He said Dar had allegedly thrown acid on the girl at Langate in Kupwara yesterday after she rejected his marriage proposal.
The girl's face and body suffered partial burn injuries in the attack and the victim is currently undergoing treatment at a hospital.
Police had yesterday arrested Dar's friend Abbas Najar who allegedly brought the acid to the scene of the incident.