The first strike, in the Jabalya refugee camp, targeted the home of a member of Islamic Jihad, a group which earlier on Monday fired at least two rockets into Israel, the army said.
Residents of the building were told to leave before the strike, but medics said eight people were injured.
Many of the wounded were bystanders, though the house's owner and his wife and children were outside the building during the attack and were also wounded, hospital officials said.
A vehicle parked outside the building was set ablaze.
The second strike, in the Bait Hanoun district of northern Gaza, hit a house where a member of the Popular Resistance Committees, a coalition of resistance groups, was living, residents of the area said.
Hussein Abu Odeh, the owner of the house, said there were no injuries.
Series of strikes
He said he had received two calls from the army warning him to leave, one just minutes before a bomb demolished the two story building.
A vehicle outside one of the
houses was set ablaze
The Israeli army said Abu Odeh's home was also used as a weapons storehouse.
Medics said one person was taken to hospital.
Israel has carried out a series of air strikes in Gaza over recent weeks, targeting suspected hideouts and factories it says are used for making make-shift rockets.
Attacks were stepped up after the June 25th kidnapping of an Israeli soldier by Gaza fighters. The soldier is still being held.