Eliza Doolittle is a fictional character who appears in the play Pygmalion (George Bernard Shaw, 1912) and, by extension, the musical version of that play My Fair Lady.

Eliza is a Cockney flower girl, who comes to Professor Henry Higgins asking for elocution lessons, after a chance encounter at Covent Garden. Higgins goes along with it for the purposes of a wager: that he can turn her into the toast of elite London society.

Doolittle receives voice coaching and learns the rules of etiquette. The outcome of these attentions varies between the original play and the various adaptations are discussed at the Pygmalion article.

The part of Eliza was originally played by Mrs Patrick Campbell, at that time the most famous actress on the London stage but considered by many to be far too old for the role. The unprecedented use of the word "bloody" - as a scripted intensive - caused a sensation when Campbell delivered it.

Joseph Weizenbaum named his artificial intelligence computer program ELIZA after this character.