The Alhambra Decree (also known as the Edict of Expulsion; Spanish: Decreto de la Alhambra, Edicto de Granada) was an edict issued on 31 March 1492, by the joint Catholic Monarchs of Spain (Isabella I of Castile and Ferdinand II of Aragon) ordering the expulsion of practising Jews from the Crowns of Castile and Aragon and its territories and possessions by 31 July of that year. The primary purpose was to eliminate the influence of practising Jews on Spain's large formerly-Jewish converso New Christian population, to ensure the latter and their descendants did not revert to Judaism. Over half of Spain's Jews had converted as a result of the religious persecution and pogroms which occurred in 1391. Due to continuing attacks, around 50,000 more had converted by 1415. A further number of those remaining chose to convert to avoid expulsion. As a result of the Alhambra decree and persecution in the years leading up to the expulsion, of Spain's estimated 300,000 Jewish origin population, a total of over 200,000 had converted to Catholicism to remain in Spain, and between 40,000 and 100,000 remained Jewish and suffered expulsion. An unknown number of the expelled eventually succumbed to the pressures of life in exile away from formerly-Jewish relatives and networks back in Spain, and so converted to Catholicism to be allowed to return in the years following expulsion.:17The edict was formally and symbolically revoked on 16 December 1968, following the Second Vatican Council. This was a full century after Jews had been openly practicing their religion in Spain and synagogues were once more legal places of worship under Spain's Laws of Religious Freedom.

In 1924, the regime of Primo de Rivera granted Spanish citizenship to the entire Sephardic Jewish diaspora. In 2014, the government of Spain passed a law allowing dual citizenship to Jewish descendants who apply, to "compensate for shameful events in the country's past." Thus, Sephardi Jews who can prove they are the descendants of those Jews expelled from Spain because of the Alhambra Decree can "become Spaniards without leaving home or giving up their present nationality."