Emergency services were at the scene on Duntocher Road, Bearsden after the incident, which happened around 4.10pm.
Police say the schoolgirl was rushed to Queen Elizabeth University Hospital in Glasgow and kept in overnight.
The road close to St Nicholas' Primary school was closed off after the incident.
A spokesperson for Police Scotland said: "About 4.03pm yesterday a one vehicle road traffic crash happened on Duntocher Road in Glasgow.
"A white coloured Toyota Aygo car was in collision with a 15-year-old female pedestrian.
"As a result the pedestrian was taken to the Queen Elizabeth University Hospital where she was kept in overnight for observation as a precautionary measure.
"The car driver was uninjured".