The 1931 Spanish local elections were held on 12 April throughout all municipalities in Spain to elect 80,472 councillors. The elections were perceived as a plebiscite on the monarchy of Alfonso XIII. After republican parties and their allies came away with a convincing victory, the king left the country and the Second Spanish Republic was proclaimed. A provisional government was formed shortly thereafter, with national elections scheduled for later in the year.

Since 1923, Spain had been a dictatorship with the approval of the reigning monarch at the time: Alfonso XIII. After the end of the Primo de Rivera dictatorship in 1930 and the failure of his successor to establish another dictatorship, in 1931 the new cabinet appointed by the king decided to hold new local elections for first time in nine years. Although they were local elections, they were perceived as a plebiscite on the Spanish monarchy, as no national elections or polls had been held since 1923.

The number of seats of each council was determined by the population count. According to the 1877 municipal law, the population-seat relationship on each municipality was to be established on the following scale:^[1]

The 1907 election law established that councillors should be elected in districts consisting of 4 members, although 3 to 7 member districts were also allowed. Voters had to choose multiple candidates using limited voting, which allows a voter to vote for fewer candidates than members have to be elected. Candidates winning a plurality of votes in each district were elected. If the number of candidates was equal or fewer than the number of seats to be filled, candidates were automatically proclaimed without an election. Voting was compulsory and on the basis of universal manhood suffrage, with males over twenty-five and at least a two-year residency in a municipality required to vote. Mayors were elected indirectly by the city or town council on the first session after the election.^[1][2]

On 14 April, two days after the election, in the cities where the republicans won the election, large crowds of people celebrated the victory on the streets. In Eibar, Barcelona, Valencia, Madrid and other cities the Second Spanish Republic was proclaimed. Eibar was the first city to fly the Spanish tricolor.

Alfonso XIII left Spain and exiled to Rome, without abdicating. A provisional government was formed and two months later general elections were called.