Cops yesterday arrested a third man in connection with the murder of a 4-year-old boy in The Bronx last week.

Ronald Jeffrey, 19, was charged with murder, attempted murder and criminal possession of a weapon for his part in Sunday’s shootout that killed tot Lloyd Morgan, police said.

Jeffrey allegedly is one of the gunmen who opened fire on a basketball court near the Forest Houses in Morrisania where Morgan was playing when he was shot in the head by a stray bullet.

Earlier this week Rondell Pinkerton, 17, was charged with the murder and Courtney Kelly, 26, who was shot during the gunfight, was charged with criminal possession of a weapon.