The 2015 Spanish regional elections were held on Sunday, 24 May 2015, to elect the regional parliaments of thirteen of the seventeen autonomous communities—Aragon, Asturias, the Balearic Islands, the Canary Islands, Cantabria, Castile and León, Castilla-La Mancha, Extremadura, La Rioja, Madrid, Murcia, Navarre and the Valencian Community—, not including Andalusia, the Basque Country, Catalonia and Galicia, which had separate electoral cycles. 804 of 1,198 seats in the regional parliaments were up for election. The elections were held simultaneously with local elections all throughout Spain.
The ruling People's Party (PP) suffered one of the harshest loss of votes for any party in the quadrennial regional elections, losing all of its absolute majorities and most of the regional administrations at stake, including notable PP strongholds such as the Valencian Community which it had held continuously since 1995. The Spanish Socialist Workers' Party (PSOE) was unable to capitalize on the PP backlash and kept losing votes from 2011. However, through post-election agreements with other left-wing parties it was able to recapture all of the regional governments it had lost four years previously, as well as gain the Valencian regional government.
The novelty of these elections was the irruption of two new parties: Podemos (Spanish: We can), a party founded in 2014 before the May European Parliament election, and Citizens (C's), a Catalan unionist party created in 2006 to run in Parliament of Catalonia elections. Podemos obtained a strong third place, close to the two main parties in several regions and entering in all regional parliaments—a first for any party aside from PP and PSOE—, while C's placed fourth in most regions, being left out from regional assemblies in the Canary Islands, Castilla-La Mancha and Navarre.
Determination of election day varied depending on the autonomous community, with each one having competency to establish its own regulations. Typically, thirteen out of the seventeen autonomous communities—all but Andalusia, the Basque Country, Catalonia and Galicia—had their elections fixed for the fourth Sunday of May every four years, to be held together with nationwide local elections.