The Sister-in-Law is a 1974 soft core sexploitation drama film written and directed by Joseph Ruben.

The plot centers around a hippie who is desired by his sister-in-law and mistaken for his underhanded brother after he returns to middle-class life.

The film was shot in JFK International Airport, Jamaica, Queens, New York City, USA.

[2] Robert Strong, a singer-songwriter who has been traveling the country, makes a mistake when he goes to visit his brother, Edward, and gets involved with his bored sister-in-law, Joanna.

Like other films distributed by Crown International Pictures, The Sister-in-Law is readily available through VOD and often included in DVD collections of similar films from the 1970s such as The Pom Pom Girls and Blue Money, through Mill Creek Entertainment and other companies.