Justin Mamo, 17, was reported missing on January 24.
He was subsequently last seen on January 26, at about 11am in Gżira wearing a black shirt and blue tracksuit trousers with white stripes.
Justin is thin and of average height.
Whoever has any information about his whereabouts is kindly asked to call 119 or 2122 4001, even in confidence, or visit the nearest police station.