The teenager was detained after a woman was inappropriately touched by the male whilst walking in Shore Crescent in north Belfast around 11 pm last night.
The male was on a bike at the time of the incident.
The male has also been arrested in connection with a similar incident which took place at around the same time at Donegal Park Avenue, Belfast on the 29th of July 2014.
If you have any information about these or similar incidents please contact police at Musgrave PSNI on 101.
Or alternatively information can be passed anonymously through Crimestoppers on the freephone 0800 555 111.