Ricky, 15, has been missing from Newhaven since August 8.
He has links to Hastings and Haywards Heath.
Ricky is skinny, 5'8", with short dark hair, and was last seen wearing a blue T-shirt, black hooded top and black jogging bottoms.
Anyone who sees him or knows his whereabouts is asked to report it to Sussex Police online and quote serial 439 of 09/08.