A 7-year old girl was sexually assaulted early last night after she left her Queens back yard to get a ball that went over a fence while she was playing, police said.

The child was behind her family’s home on Sutter Avenue near 115th Street in South Ozone Park at around 6 p.m. when she encountered the stranger who attacked her.

She was later taken to Queens General Hospital.

Police cordoned off the block late last night and were searching for the suspect.