It happened around 9:45 p.m. on the 2000 block of East Clementine Street, the department said.
The girl was shot in the stomach and rushed to the Children's Hospital of Philadelphia, where she was placed in stable condition, according to police.
The second victim, a 24-year-old man, was hit in the left calf and back and is also in stable condition, they added.
No weapons were recovered from the scene and no arrests had been made as of early Thursday. Aug. 10.
Click here to follow Daily Voice Lancaster and receive free news updates.