Police said that a group of about 20 people were involved in the attack on the 17-year-old in Croydon, south-east London, which they said was being treated as a hate crime.
The Press Association said the teenager was Kurdish Iranian and suffered a fractured skull and a blood clot on his brain. Police have not identified the victim.
Four people were charged with violent disorder, and one with violent disorder and grievous bodily harm, police said, They will appear in court later.
Teenager in hospital
