Next Spanish general election

The next Spanish general election will be held no later than Sunday, 22 August 2027, to elect the 16th Cortes Generales of the Kingdom of Spain. All 350 seats in the Congress of Deputies will be up for election, as well as 208 of 265 seats in the Senate.

The inconclusive result of the 2023 election raised the possibility of a repeat election being held by late 2023 or early 2024. However, an agreement was ultimately reached between the Spanish Socialist Workers' Party (PSOE) and Together for Catalonia (Junts) to support the re-election of incumbent Prime Minister Pedro Sánchez in exchange of a controversial amnesty law for Catalan politicians convicted or investigated for events related to the 2017–2018 Spanish constitutional crisis and the 2019–2020 Catalan protests. Sánchez's investiture was materialized on 16 November 2023, allowing him to form his third cabinet.

Electoral system
The Spanish Cortes Generales are envisaged as an imperfect bicameral system. The Congress of Deputies has greater legislative power than the Senate, having the ability to vote confidence in or withdraw it from a prime minister and to override Senate vetoes by an absolute majority of votes. Nonetheless, the Senate possesses a few exclusive (yet limited in number) functions—such as its role in constitutional amendment—which are not subject to the Congress' override. Voting for the Cortes Generales is on the basis of universal suffrage, which comprises all nationals over 18 years of age and in full enjoyment of their political rights.

For the Congress of Deputies, 348 seats are elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of three percent of valid votes—which includes blank ballots—being applied in each constituency. Seats are allocated to constituencies, corresponding to the provinces of Spain, with each being allocated an initial minimum of two seats and the remaining 248 being distributed in proportion to their populations. Ceuta and Melilla are allocated the two remaining seats, which are elected using plurality voting. The use of the electoral method may result in an effective threshold based on the district magnitude and the distribution of votes among candidacies.

As a result of the aforementioned allocation, each Congress multi-member constituency would be entitled the following seats (as of 23 December 2023):

For the Senate, 208 seats are elected using an open list partial block voting system, with electors voting for individual candidates instead of parties. In constituencies electing four seats, electors can vote for up to three candidates; in those with two or three seats, for up to two candidates; and for one candidate in single-member districts. Each of the 47 peninsular provinces is allocated four seats, whereas for insular provinces, such as the Balearic and Canary Islands, districts are the islands themselves, with the larger—Majorca, Gran Canaria and Tenerife—being allocated three seats each, and the smaller—Menorca, Ibiza–Formentera, Fuerteventura, La Gomera, El Hierro, Lanzarote and La Palma—one each. Ceuta and Melilla elect two seats each. Additionally, autonomous communities can appoint at least one senator each and are entitled to one additional senator per each million inhabitants.

Election date
The term of each chamber of the Cortes Generales—the Congress and the Senate—expires four years from the date of their previous election, unless they are dissolved earlier. The election decree shall be issued no later than the twenty-fifth day prior to the date of expiry of parliament and published on the following day in the Official State Gazette (BOE), with election day taking place on the fifty-fourth day from publication. The previous election was held on 23 July 2023, which means that the legislature's term will expire on 23 July 2027. The election decree must be published in the BOE no later than 29 June 2027, with the election taking place on the fifty-fourth day from publication, setting the latest possible election date for the Cortes Generales on Sunday, 22 August 2027.

The prime minister has the prerogative to dissolve both chambers at any given time—either jointly or separately—and call a snap election, provided that no motion of no confidence is in process, no state of emergency is in force and that dissolution does not occur before one year has elapsed since the previous one. Additionally, both chambers are to be dissolved and a new election called if an investiture process fails to elect a prime minister within a two-month period from the first ballot. Barred this exception, there is no constitutional requirement for simultaneous elections for the Congress and the Senate. Still, as of 2024 there has been no precedent of separate elections taking place under the 1978 Constitution.

Parliamentary composition
The tables below show the composition of the parliamentary groups in both chambers.

Parties and candidates
The electoral law allows for parties and federations registered in the interior ministry, coalitions and groupings of electors to present lists of candidates. Parties and federations intending to form a coalition ahead of an election are required to inform the relevant Electoral Commission within ten days of the election call, whereas groupings of electors need to secure the signature of at least one percent of the electorate in the constituencies for which they seek election, disallowing electors from signing for more than one list of candidates. Concurrently, parties, federations or coalitions that have not obtained a mandate in either chamber of the Cortes at the preceding election are required to secure the signature of at least 0.1 percent of electors in the aforementioned constituencies. The electoral law provides for a special, simplified process for election re-runs, including a shortening of deadlines, electoral campaigning, the lifting of signature requirements if these had been already met for the immediately previous election and the possibility of maintaining lists and coalitions without needing to go through pre-election procedures again.

Below is a list of the main parties and electoral alliances which will likely contest the election: