Giuliana De Sio (Salerno, 2 April 1956) is an Italian actress, winner of two David di Donatello awards.

Her first main role was in 1977 RAI TV film Una donna, based on the novel by Sibilla Aleramo. The following year she was given a part in the Rai TV series Le mani sporche (Dirty Hands), alongside Marcello Mastroianni. De Sio was romantically involved for four years with Elio Petri, whom she met during the filming of the series, directed by him. She lived with him until his untimely death in 1982.

De Sio had her breakout in 1983, when she starred in Massimo Troisi's Scusate il ritardo and alongside Francesco Nuti in Maurizio Ponzi's The Pool Hustlers, that got her a David di Donatello for Best Actress and a Nastro d'Argento for Best Actress. She won a second David di Donatello for Carlo Lizzani's The Wicked.