Ralph Roister Doister is a comedy by Nicholas Udall, generally regarded as the first to be written in the English language.

It was written in about 1553, when Udall was a teacher in London, and was intended to be performed by his pupils - who were all male, as were all actors at that period. However, it was not published until 1567, eleven years after its author's death.

The play is probably best described as a farce, and owes something to the Latin playwrights, Plautus and Terence.