The man drove past the bus stop twice before exiting his vehicle and exposing himself to the victim.
Police are now appealing for information in connection with the incident.
It took place at the end of Buffery Road, close to the junction with Lister Road at around 8pm on July Tuesday 26.
A spokesperson for West Midlands Police said: "We received a report that on Tuesday 26 July, between 8pm and 8.15pm a man exposed himself to a young girl at the bus stop at the end of Buffery Road, close to the junction with Lister Road.
"He drove past twice before exiting his vehicle to expose himself opposite the bus stop from the victim.
"Enquiries are ongoing. If you have any information regarding this incident please message us via the live chat on our website."
Information can also be passed on by calling 101, quoting reference 4157 of July 26. Alternatively contact Crimestoppers, anonymously, on 0800 555 111.