A 15-month-old Long Island girl was killed yesterday when her grandmother lost control of the SUV she was driving, authorities said.

Terrayjah Burwell, who police said was in a car seat but “not properly restrained,’’ was ejected from the vehicle and died at the scene.

The SUV overturned at about 1 p.m. and wound up on the median of Suffolk County Road 83.

The driver, Corenthea Skipwith, 50, of Mastic, and the girl’s mother, Natoya McCoy, 28, were hospitalized with non-life-threatening injuries.