The attack happened in Coronation Gardens, Sedgley, on Saturday night, which saw the victim taken to hospital.
West Midlands Police is appealing for any witnesses to come forward.
A force spokesman said: "Police were called to Dudley Street, Sedgley, at around 8.20pm on Saturday following reports that a 27-year-old man had been assaulted.
"It is believed he was hit on the head with a bottle in nearby Coronation Gardens, following a row with a number of teenage boys.
"The victim was taken to hospital for treatment."
Anyone with information has been asked to contact police and quote log 20DY/224498H/19.
