Robert John Wagner (born February 10, 1930) is an American actor of stage, screen, and television.

A veteran of many films in the 1950s and 1960s, Wagner gained prominence in three American television series that spanned three decades: It Takes a Thief (1968–70), Switch (1975–78), and Hart to Hart (1979–84). In movies, Wagner is known for his role as Number Two in the Austin Powers films (1997, 1999, 2002). He also had a recurring role as Teddy Leopold on the TV sitcom Two and a Half Men.

Wagner's autobiography, Pieces of My Heart: A Life, written with author Scott Eyman, was published on September 23, 2008.