The 14-year-old was approached by three young men in High Street, Paisley, near the Cenotaph, at about 8.30pm on Sunday, 6 June
The attackers assaulted the teenage boy and stole his mobile phone before one of them ran away and other two cycled off at speed on bikes.
The suspects have been described as white and one is aged around 18 years old while the other two are about 16.
At the time of the assault, one of the attackers was wearing a black hat, black and white tracksuit top and red joggers, another was wearing a grey hooded jumper, black joggers and black trainers and the third was dressed in a black and white hooded top, black joggers and black trainers.
Several people were seen in the area at the time, some of whom were filming the incident on their phones.
Officers are also reviewing CCTV image for any additional information on the incident and the suspects.
Detective Constable Stuart Crawford said: “We know there were people who saw and heard what happened to the young boy. We are also aware that the incident and aftermath was filmed. This footage is vital to our enquiries and I would appeal to those who have mobile phone footage to please pass it on to us. Those images will greatly assist our enquiries and help us identify those responsible for the attack on a 14-year-old boy.”
Anyone with information is asked to call Police Scotland via 101, quoting incident number 0056 of 6 June, 2021.