Police have issued an appeal for public help in finding and identifying the unknown man who is believed to be in his 40s.
The incident happened at the bus stop opposite the Royal Hall on Ripon Road, at around 4.50pm on Monday, May21.
North Yorkshire Police said: " The victim, a 16-year-old school girl was sat waiting for her bus when she was approached and punched in the face by an unknown man."
The man is described as white, aged about 40 years old and 5ft 9in tall.
He had a bald head and was wearing a bright green t-shirt with a logo in the middle and khaki coloured shorts.
Police are appealing to anyone with information, but in particular, to anyone who may have been in the area at the time and witnessed the incident take place.
Anyone with information that could assist the investigation should contact North Yorkshire Police on 101, select option 2, and ask for PC 614 Ross Baldwin.
You can also email [email protected]
If you wish to remain anonymous, you can pass information to Crimestoppers on 0800 555 111.
Please quote the North Yorkshire Police reference number 12180089142.