Fifteen-year-old Ramandeep Singh was posing with his father's .32 caliber pistol on Friday evening when he accidentally pulled the trigger, according Manoj Kumar, Deputy Superintendent of Police in Pathankot, Punjab state.
The safety catch wasn't on, police said.
Statistics released earlier this year put India top of the list for selfie-related deaths.
Of 49 fatalities over three years worldwide, India accounted for 19 - nearly 40% of the global total.
Police are instructed to step in if they see anyone attempting to take selfies in high-risk locations, including the seafront, a popular area for young people carrying selfie sticks.
