Police were called to reports of a fight on the Old Kent Road, SE1, on Thursday evening (October, 3) and found a teenager with slash wounds.
The male in his late teens was taken to hospital and his injuries are not thought to be life-threatening.
No arrests were made, but police would like to hear from anyone witnesses.
The incident occured around 6.20pm.
If you have any information call 101 and quote CAD6634/3 or Crime-stoppers.