The Diet of Worms 1521 (, ) was an imperial diet of the Holy Roman Empire held at the Heylshof Garden in Worms, then an Imperial Free City of the Empire. An imperial diet was a formal deliberative assembly of the whole Empire. This one is most memorable for the Edict of Worms (Wormser Edikt), which addressed Martin Luther and the effects of the Protestant Reformation. It was conducted from 28 January to 25 May 1521, with the Emperor Charles V presiding.