Henri Cain (11 October 1857 – 21 November 1937) was a French dramatist, opera and ballet librettist. He wrote over forty librettos from 1893 to his death, for many of the most prominent composers of the Parisian Belle Epoque.
Cain was born in Paris, the son of the sculptor Auguste Cain and brother of the painter Georges Cain. He studied painting in the studios of Jean-Paul Laurens and Édouard Detaille. He was married to the soprano Julia Guiraudon.
Close to Edouard de La Gandara, Jean Dara when he worked with Sarah Bernhardt, Henri Cain was an admirer of several major contemporary painters and sculptors such as Antonio de La Gandara and Jean Carriès.