Otto Wilhelm Fischer (April 1, 1915 – January 29, 2004) was an Austrian actor. A leading man of German cinema, he began his career with Max Reinhardt's stage company.

He was born in Klosterneuburg near Vienna. While he enjoyed a great career, unlike countrymen Oskar Werner, Curd Jürgens, Maria Schell and Romy Schneider, he never made it internationally. Worse, his American break ended before it began: he was signed to star with June Allyson in a remake of My Man Godfrey in 1956, but was replaced by David Niven when Fischer reportedly lost his memory during filming. Fischer directed and starred opposite Anouk Aimée in a 1953 film, Ich suche Dich, based on the play, Jupiter Laughs, by A.J. Cronin. In 1955, he directed and starred in a movie detailing the life of Erik Jan Hanussen, the Devil's Prophet. While the film is considered highly romanticized, it assisted historians and biographers in uncovering previously unknown facts. He also starred in the title role in the classic German film, Ludwig II.

In the early 1970s, he retired to concentrate on linguistics and philosophy, on which he lectured and published a number of books. He died in Lugano, Switzerland of kidney failure.

Began his career with Max Reinhardt's stage company.

His breakthrough in Hollywood failed, although he was signed to star with June Allyson in My Man Godfrey (1957). When he reportedly lost his memory during filming, he was replaced by David Niven (I).

Being one half of German cinema's dream couple with Maria Schell (I) in the 1950s, he became the best paid actor in Germany at that time.

Moved to Vernate, Switzerland with his wife Anna in the 1960s.

Ensemble member at the famous Vienna Burgtheater from 1945 to 1952.

Retired from acting to lecture and publish books on linguistics and philosophy in the early 1970s.