NoLIbs is trying to reduce crime since the brutal murder of Sabina Rose O'Donnell in June.
Police are seeking two suspects in the apparent murder, which was reported at about 11:30 p.m. at the school, located at 400 Murchison Drive.
Officers arrived to find the victim suffering from multiple wounds. He was pronounced dead at the scene, police said.
Kirk Black, spokesman for the San Mateo Union High School District, said the victim was apparently stabbed near the on-campus tennis courts. He said the tennis courts abut a public skate park and bicycle path that is a gathering place for youth.
Black said he does not know if the death occurred on school property or just off it.
Investigators say there were witnesses to the killing and were conducting interviews this morning.
The suspects are believed to be two men. One is described as a Samoan male about 18 or 19 years old, 6 feet 2 inches tall and 130 pounds. He was wearing a black hooded sweatshirt, a white T-shirt, black shorts and low-top shoes.
The other suspect is described as a Pacific Islander man between 22 and 23 years old, 6 feet 1 inch tall and 180 pounds with a muscular build.
He had a black beard and was wearing a beanie, a vest and black hooded sweatshirt, black pants, basketball shoes, and was carrying a backpack, according to police.
Black said the incident is not affecting the school because classes are out for the summer. School is scheduled to resume Aug. 16.