<p>Legitimacy is an overlooked precondition for a tactic’s availability within social movement repertoires. Drawing on semi-structured interviews with 37 Movement for Black Lives activists in Minneapolis and St. Paul, Minnesota, this article identifies a three-step process through which activists legitimize riots. First, activists reclassify riots as protest by lumping them with revered tactics, thereby splitting them from criminality. Second, activists engage in moral legitimation: they acknowledge the harm riots can cause to Black communities but frame them as justified counterviolence to state repression. Third, activists use instrumental legitimation. Despite potential reputational risks, they argue that riots impose costs on capitalism, delegitimize the state and lend credibility to subsequent nonviolent protests. By tracing how activists legitimate a controversial movement tactic, this article argues that legitimation work shapes tactical availability. This challenges views of the repertoire of contention as a fixed toolkit from which activists choose tactics they regard as strategically effective or aligned with their collective identities.</p>