The teenage girl was reportedly assaulted at 4pm on November 22 on the number 44 Stagecoach bus as it was heading into the city centre on Chesterfield Road South.
The victim was held in a headlock by a woman following an argument with a group of secondary school pupils on the upper deck of the bus.
The victim was not injured during the incident.
Enquiries into the incident remain ongoing and officers are now keen to identify the woman pictured.
She is described as white, 40 years old, of slim build and between 5ft 4ins to 5ft 7ins tall, with straight, light brown hair tied back.
She was wearing a dark coloured winter coat with fur trim around the hood.
Anyone who recognises the woman can call police on 101 quoting incident 552 of November 22.