The Sex Thief is a 1973 British sex comedy film starring David Warbeck, Diane Keen and Christopher Biggins. It was an early film credit for director Martin Campbell.

The film was released in North America (in January 1976) as Her Family Jewels, with added hardcore inserts performed by stand-ins for the original cast members.

Keen, quoted in the book The Worlds Greatest Scandals of the 20th Century, claimed: "Times were pretty hard and this is a comedy which I am not ashamed at having made. But it was bought by a company, which drafted in other actresses to make it look like I was doing erotic things from start to finish. It became incredibly filthy." The hardcore version was later released on video in The Netherlands (under the name Handful of Diamonds).

The film was written by Tudor Gates and Michael Armstrong under the name Edward Hyde.

During the 2007 series of I'm a Celebrity... Get Me Out of Here!, Biggins failed to get a question right about his character's name in the film as part of a bushtucker trial. He groaned, "The Sex Thief, God, that was a million years ago."