A supermajority, supra-majority, qualified majority, or special majority is a requirement for a proposal to gain a specified level of support which is greater than the threshold of more than one-half used for a simple majority. Supermajority rules in a democracy can help to prevent a majority from eroding fundamental rights of a minority, but they can also hamper efforts to respond to problems and encourage corrupt compromises in the times action is taken. Changes to constitutions, especially those with entrenched clauses, commonly require supermajority support in a legislature. Parliamentary procedure requires that any action of a deliberative assembly that may alter the rights of a minority have a supermajority requirement, such as a two-thirds vote.

Related concepts regarding alternatives to the majority vote requirement include a majority of the entire membership and a majority of the fixed membership. A supermajority can also be specified based on the entire membership or fixed membership rather than on those present and voting.