Tweedledum and Tweedledee are characters in an English nursery rhyme and in Lewis Carroll's 1871 book Through the Looking-Glass, and What Alice Found There.

The names have since become synonymous in western popular culture slang for any two people whose appearances and actions are identical.

Common versions of the nursery rhyme include: The words "Tweedle-dee and Tweedle-dum" make their first appearance in print as names applied to the composers George Frideric Handel and Giovanni Bononcini in "one of the most celebrated and most frequently quoted (and sometimes misquoted) epigrams", satirising disagreements between Handel and Bononcini,[2] written by John Byrom (1692–1763):[3] in his satire, from 1725.

Carroll, having introduced two fat little men named Tweedledee and Tweedledum, quotes the nursery rhyme, which the two brothers then go on to enact.

Rather, they complement each other's words, which led John Tenniel to portray them as twins in his illustrations for the book.