Witches' Brew, also known as Which Witch Is Which?, is a 1980 American comedy horror film co-written and directed by Richard Shorr, and starring Richard Benjamin, Teri Garr, and Lana Turner. It was based (though without any screen credit) on Fritz Leiber Jr.'s horror-fantasy novel Conjure Wife. Herbert L. Strock directed additional sequences for the film.

The film is set in a college campus. The wives of several academics practice witchcraft to advance their husbands' careers. A skeptical husband convinces his wife to cease practicing witchcraft, and then experiences a decline in his career and an attack by a disgruntled student. Meanwhile, a dying witch is trying to use a body swapping technique to eliminate the professor's wife.