Roberto Chiacig (born 1 December 1974 in Cividale del Friuli, Italy) is an Italian former professional basketball player, still playing at an amateur level.

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.

Chiacig grew up in the youth ranks of Benetton Treviso, making his debut for the side in a first division Serie A game on 6 February 1994, playing 4 minutes.

Joining Montepaschi Siena in 2000, he spent 6 seasons with the club, winning the 2001–02 FIBA Saporta Cup, the 2003–04 Lega Basket Serie A and another Italian Supercup in 2004.