Arcadia police said gunfire rang out at a house party near Caroline Way, south of Las Tunas Drive just before 9 p.m.
The victim was taken to a hospital, where he later died.
There were between 20 to 30 people at the house party, according to police.
A person was arrested on a weapons charge, but police are still determining if the person in custody was involved in the shooting.
Details regarding what led to the shooting were unknown.