The incident happened shortly after 2 p.m. PT at Princess Margaret Secondary school in the 12800 block of 72nd Avenue.
Surrey RCMP Cpl. Bert Paquet said police are now searching for the suspect, who fled on foot and is believed to be another high school student.
Police are investigating the relationship between the suspect and the victim, but believe there to be no risk to the public at this time.
"Based on the information we have we do believe that this incident was targeted by the suspect toward the victim," Paquet said. "The knife has been recovered as well so there is no risk toward public safety at this point."
The extent of the victim's injuries are unknown at this time.