The boy, aged 14, was chased by three teenagers through Dale End Car Park towards the River Severn then stabbed when he fell into a flower bed near the antiques, arts and crafts centre.
The three attackers then fled towards the main road, West Mercia Police said, and the injured boy was taken to Birmingham Children's Hospital. He is not thought to have been seriously hurt.
Three boys, aged 12, 13 and 14, were arrested after the attack happened at around 4.10pm on Sunday, on suspicion of causing grievous bodily harm. They have since been released on bail.
Police are now appealing for any witnesses to come forward.
Det Sgt Goddard, from Telford police, said: " We currently have extra patrols in place following this understandably distressing incident.
"CCTV shows a number of people in the area at the time of the incident. If you were in the area or saw this incident please contact me on 01952 214712 quoting reference 424i March 27."
Jamie Arrowsmith from West Midlands Ambulance Service confirmed that an ambulance and a paramedic officer attended the incident.
"On arrival they discovered one patient, a teenage male. He was treated for stab injuries which were not believed to be serious.
"He was taken to hospital for further treatment."