Police said three grenades were detonated in rapid succession in three sections of the Shama Cinema theater during a movie showing, Geo TV News reported.
"The first hand grenade was detonated in the front, second in the rear followed by the third blast in the cinema," said Capital City Police Officer Ijaz Ahmed.
Shama Cinema's owners have told media outlets they had been receiving threats and were told to increase security measures including installing security cameras, Geo TV News said.
Dawn News said about 70 people were watching a movie when the blasts occurred.
Tuesday's attack is the second at a Peshawar movie house this month. On Feb. 2, five people were killed and 20 injured when two hand grenades were detonated during a late-night movie show at the Picture House cinema.