The 2015 Spanish general election was held on Sunday, 20 December 2015, to elect the 11th Cortes Generales of the Kingdom of Spain. All 350 seats in the Congress of Deputies were up for election, as well as 208 of 266 seats in the Senate. At exactly four years and one month since the previous general election, this remains the longest timespan between two general elections since the Spanish transition to democracy, and the only time in Spain a general election has been held on the latest possible date allowed under law.

The Congress of Deputies is the lower house of the Cortes Generales, Spain's legislative branch, the upper house being the Senate. The Congress meets in the Palace of the Parliament in Madrid.