Baby Sister is a 1983 American made-for-television drama film directed by Steven Hilliard Stern.

The film, which stars Phoebe Cates, Ted Wass and Pamela Bellwood, centers on a 19-year-old woman who starts an affair with her older sister's boyfriend and premiered on ABC on March 6, 1983.

Fearing to face her father, she packs her stuff and moves in with her older sister Marsha, who runs her own gallery in Los Angeles.

The next evening, Annie serves as a replacement for Marsha, who was supposed to attend a play with David, but wasn't able to make it.

He plans on telling Marsha the truth, but Annie discourages him from doing so, afraid to hurt her sister's feelings.

Unable to face her sister anymore, she decides to return to college after attending Marsha's gallery opening.

In the end, just before leaving L.A., Annie is reconciled with both Marsha and her father, the latter assuring her she is not responsible for her mother's death.