Arnold Weinstein (June 10, 1927–September 4, 2005) was an American poet, playwright and librettist, who referred to himself as a "theatre poet".

Weinstein is best known for his collaborations with composer William Bolcom, including the operas McTeague, based on the novel by Frank Norris, A View from the Bridge based on the play by Arthur Miller, and A Wedding, based on the film by Robert Altman. Bolcom described his work with Weinstein as a "true collaboration", and said about him that "He had such a gift for writing words that were singable, and that gave character. He was more influential on a lot of other people than people have taken into account."