Police and medics were called to an Escondido party just before midnight on Saturday.
Officers found 16-year-old Alexis Magadan lying in the driveway of North Rose Street with a stab wound to his chest.
Magadan was pronounced dead on the scene despite attempts to resuscitate him.
The teen was stabbed at the house where the party was held, then stumbled across the street to another resident's driveway, according to one neighbor.
Family and friends set up a small memorial in that driveway.
A second stabbing victim was taken to Palomar Hospital with non-life threatening injuries.
Witnesses say the two were stabbed during a fight at the party.
Investigators haven't yet released a suspect description and don't know the motive of the stabbing either.