Police were called to an address at Wembley Road in Gorton at about 1930 BST to deal with reports of a shooting.
Police and ambulance crews attended and the girl was taken to Manchester Royal Infirmary suffering from a gunshot wound to the head.
A 17-year-old boy from Gorton has been arrested on suspicion of attempted murder. He will be questioned later.
Most Popular Now | 37,800 people are reading stories on the site right now.";