Tybalt kills Mercutio in a street fight in Romeo and Juliet. Tybalt, a Capulet and Juliet’s cousin, challenges Romeo after the Capulet ball, but Romeo refuses to fight because he has secretly married Juliet and now considers Tybalt family.
Mercutio, Romeo’s friend, does not share Romeo’s restraint. He fights Tybalt and is fatally wounded when Romeo steps between them. Mercutio initially treats the injury as a joke, but his wound proves deadly. His dying curse—“A plague o’ both your houses”—condemns both feuding families.
Romeo then kills Tybalt in anger. This single street battle changes the play’s direction: the comic energy of the earlier scenes gives way to exile, failed communication, and the lovers’ increasingly desperate plan. The death is sometimes misremembered as a direct duel between Romeo and Tybalt; Romeo kills Tybalt only after Tybalt has killed Mercutio.