Roberto Chiacig (born 1 December 1974 in Cividale del Friuli, Italy) is an Italian professional basketball player for Gecom Mens Sana 1871 Siena of the Serie B Basket.
Playing as a center, his most notable achievement was the silver medal obtained by the Italian national team, of which he was a member, at the 2004 Summer Olympics.
Beyond playing internationally, he also has had a long club career in Italy, and abroad, winning an Italian League championship title with Montepaschi Siena.