The woman was struck at approximately 6:45 p.m. Tuesday at the intersection of 5th Street and Godfrey Avenue.
Police say the woman was crossing the street southbound when she was struck by the bus that was turning left on to Godfrey Avenue from 5th Street, resulting in the woman's legs being trapped beneath the left front tire.
Fire crews responded and managed to lift the bus off the woman.
The woman suffered what is described as "a severely crushed" right leg. She was then rushed by medics to Albert Einstein Medical Center for care.
The Route K bus runs from Ridge-Midvale to the Arrott Transportation Center.
Police are investigating.