The Secret of a Marriage (German: Geheimnis einer Ehe) is a 1951 West German comedy film directed by Helmut Weiss and starring Olga Chekhova, Curd Jürgens and Paul Klinger.

The film's sets were designed by the art directors Fritz Lück and Hans Sohnle.

A widow for fifteen years, Tina Camphausen has raised her three children by herself.

Then her first lover, the conductor Felix Adrian, comes back into her life.

Her growing affection for him offends her son Christian, who resents the newcomer moving into their house.