A general election was held in Spain on 21 August 1881 (for the Congress of Deputies), and on 2 September 1881 (for the Senate), to elect the members of the 2nd Cortes under the Spanish Constitution of 1876, during the Restoration period. All 432 seats in the Congress of Deputies were up for election, as well as 180 of 360 seats in the Senate.

Following the Bourbon Restoration in 1874, the Spanish Constitution of 1876 enshrined Spain as a semi-constitutional monarchy, awarding the monarch—under the royal prerogative—the right of legislative initiative together with the bicameral Cortes; the capacity to veto laws passed by the legislative body; the power to appoint government members (including the prime minister); the ability to grant or deny parliamentary dissolution, the adjournment of legislative sessions and the signature of royal decrees; as well as the title of commander-in-chief of the armed forces. The monarch would play a key role in the turno system by appointing and dismissing governments, which would then organize elections to provide themselves with a parliamentary majority. This informal system allowed the two major "dynastic" political parties at the time, the Conservatives and the Liberals—characterized as oligarchic, elite parties with loose structures dominated by internal factions, each led by powerful individuals—to alternate in power by means of electoral fraud (pucherazo). This was achieved by assigning candidates to districts before the elections were held (encasillado), then arrange their victory through the links between the Ministry of Governance and the territorial clientelistic networks of provincial governors and local bosses (the caciques), excluding minor parties from the power sharing.

Under the 1876 Constitution, the Spanish Cortes were conceived as "co-legislative bodies", forming a nearly perfect bicameral system. Both the Congress of Deputies and the Senate exercised legislative, oversight and budgetary functions, sharing almost equal powers, except in budget laws (taxation and public credit)—whose first reading corresponded to Congress—and in impeachment processes against government ministers, where Congress handled indictment and the Senate the trial.

The term of each chamber of the Cortes—the Congress and one-half of the elective part of the Senate—expired five years from the date of their previous election, unless they were dissolved earlier. The previous elections were held on 20 April 1879 for the Congress and on 3 May 1879 for the Senate, which meant that the chambers' terms would have expired on 20 April and 3 May 1884, respectively.

The monarch had the prerogative to dissolve both chambers at any given time—either jointly or separately—and call a snap election. There was no constitutional requirement for concurrent elections to the Congress and the Senate, nor for the elective part of the Senate to be renewed in its entirety except in the case that a full dissolution was agreed by the monarch. Still, there was only one case of a separate election (for the Senate in 1877) and no half-Senate elections taking place under the 1876 Constitution.

The Cortes were officially dissolved on 25 June 1881, with the corresponding decree setting election day for 21 August (Congress) and 2 September 1881 (Senate) and scheduling for both chambers to reconvene on 20 September.

Voting for the Congress of Deputies was based on censitary suffrage, comprising Spanish national males over 25 years of age who met either of the following:

In the Spanish West Indies (Cuba and Puerto Rico) the taxpayer requirement was higher (Pts 125, or $25), while former Cuban slaves were barred from voting until three years after becoming freedmen. In the Basque Provinces and Navarre—where taxes were not paid directly—voters had instead to prove wealth equivalent to an income of Pts 4,800; or Pts 2,400 in real estate, crops or livestock. Additional restrictions excluded those deprived of political rights or barred from public office by a final sentence, criminally imprisoned or convicted, legally incapacitated, bankrupt, and public debtors.