A woman and her 8-year-old grandson were struck by a car while crossing a Queens street Saturday, police said.

The grandmother, 56, and the boy were crossing the street in the area of Jamaica Avenue and 115th Street in Richmond Hill around 11:10 a.m. when they were struck by a Toyota Tundra as the driver was making a left turn, cops said.

Both victims, who were believed to have been within the crosswalk at the time, were initially pinned by the truck, cops said.

Khalid Lachkar, a 38-year-old food vendor from Fresh Meadows, said he heard a “boom” and turned around to see the aftermath of the accident.

“I saw a kid and woman under the car,” Lachkar said. “There were people trying to get them out. They were screaming.”

“Then a man came running over. He was yelling, ‘That’s my son. That’s my son.'”

The woman was rushed to Jamaica Hospital Medical Center in critical condition. The boy, who Lachkar said was bleeding from his face, was taken to Long Island Jewish Medical Center, where he was listed in stable condition, police said.

It was not immediately clear if the driver, who remained at the scene, would be charged.