The 17-year-old was walking on The Broadway near to a local area known as ‘The Ruins’ on Wednesday 28 January just before 11am when a man described as in his late 20s walked towards her and exposed himself.
The teenager ran towards the college where she raised the alarm and the police were called.
The man is described as around 5ft 10″ tall with a ruddy complexion. He had a full beard and moustache that was ginger and grey in colour and was last seen wearing blue flared jeans and a red and blue type jacket.
Detectives have now launched an investigation and are appealing to anyone who was in the area at the time to come forward.
Detective Constable Michelle Phillips, from Dudley’s Child Abuse Investigation Unit, said: “A full area search was conducted by officers on the day of the incident but unfortunately the man was not found.
“Officers continue to search the area for CCTV and make enquiries but I now need people who know this man or may have seen this incident to come forward.
“The teenager was obviously very upset and shaken by her ordeal but she has been very brave in reporting this and supplying a description of the offender.
“This would have happened in a very busy area at a busy time of day and I am sure someone will be able to help supply further information that may help us catch this man.”
Anyone with information is urged to call police at Dudley on 101.
Alternatively people can leave information anonymously by calling Crimestoppers the independent charity on0800 555 111.