Sieghardt Rupp (14 June 1931 – 20 July 2015) was an Austrian actor who performed in film, television and theatre.

He made over 55 film and TV appearances beginning in 1959, with his career peaking in the 1960s. He became known for his performances in gangster or Western films in the 1960s where he typically portrayed a bandit or mercenary. His dark features, similar to those of his Italian co-stars meant that he could play Latin characters, such as Mexicans.

His most noted Western performance was his role as Esteban Rojo in Sergio Leone's 1964 production A Fistful of Dollars alongside Clint Eastwood and Gian Maria Volonté. He appeared in many other Westerns in the 1960s such as Blood at Sundown (1966) although he appeared in the romantic adventure Angelique and the Sultan in 1968.