A 15-year-old schoolboy was subjected to "vile, homophobic abuse", before he was assaulted in broad daylight by a group of teenagers in Bury.
The boy challenged his abusers, before they violently attacked him on Monday afternoon, Greater Manchester Police said.
He was taken to hospital and has since been discharged.
"This was a cowardly attack on a young man who was subjected to vile, homophobic abuse," said chief inspector Phil Spurgeon. "After challenging his abusers, he was then assaulted by a number of offenders and had to be treated in hospital for his injuries.
“We are treating this offence with the upmost seriousness. We will not tolerate hate crime and will do everything in our power to apprehend offenders."
A 15-year-old boy has been arrested on suspicion of assault and remains in custody.
“While we have arrested one person, we are continuing to appeal for information on this crime and would ask that anyone if information contacts police immediately," Mr Spurgeon said.
Anyone with information should call police on 0161 856 8172 or the independent charity Crimestoppers, anonymously, on 0800 555 111.
