Officers responded to reports of a stabbing at Plaza de Cesar Chavez near Almaden Boulevard and Park Avenue at about 8:50 p.m.
The victim was taken to a local hospital injuries that were not believed to be life threatening.
Witnesses told police that three suspects in their teens or early 20s were seen fleeing the area. Police believe the stabbing was gang related. No arrests have been made.
Officials say it is highly unusual for violent crimes to occur at Christmas in the Park, which attracts nearly a half-a-million visitors each year.
Anyone with information about the case is asked to contact the San Jose Police Department gang investigation unit at (408) 277-4165.
(ABC7 News contributed to this report)