The Gracchi brothers were two brothers who lived during the beginning of the late Roman Republic: Tiberius Gracchus and Gaius Gracchus.

They served in the plebeian tribunates of 133 BC and 122–121 BC, respectively. They have been received as well-born and eloquent advocates for social reform who were both killed by a reactionary political system; their terms in the tribunate precipitated a series of domestic crises which are viewed as unsettling the Roman Republic and contributing to its collapse.