A snap legislative election was held on 10 March 2024 to elect members of the Assembly of the Republic to the 16th Legislature of Portugal. All 230 seats to the Assembly of the Republic were up for election. The elections were called in November 2023 after Prime Minister António Costa's resignation following an investigation around alleged corruption involving the award of contracts for lithium and hydrogen businesses.

No party achieved an absolute majority of seats, with the centre-right Democratic Alliance (AD), led by Luís Montenegro, winning 80 seats, closely followed by the Socialist Party (PS), which lost the absolute majority it had gained in the 2022 elections, and was reduced to 78 seats. The election also saw the surge of the right-wing populist Chega party as the third-largest party in parliament, more than quadrupling its previous seat count to 50 seats. Turnout in the election was 59.9 percent, the highest since 2005, and in Portugal alone, turnout rose to 66.2 percent, the highest rate since 1995.

The leader of the largest party, Luís Montenegro, would go on to form a centre-right minority government, ending nearly a decade of rule by the Socialist Party.

Background The Socialist Party (PS), led by Prime Minister António Costa, won an absolute majority in the 2022 legislative election with 41 percent of the votes and 120 seats in the 230 seat Assembly of the Republic. The main opposition party, the Social Democratic Party (PSD), got 77 seats and 29 percent of the votes, while the populist party Chega (Enough) gained 12 seats and seven percent. The Liberal Initiative (IL) were able to win eight seats and gather almost five percent of the votes. The far-left parties, the Portuguese Communist Party (PCP) and the Left Bloc (BE), achieved one of their worst results ever with four percent of the votes and six and five seats, respectively. PAN and LIVRE were able to win just one seat each.

António Costa's third government was sworn in on 30 March 2022. This government proved to be rather unstable, having experienced numerous scandals and controversies, and despite overseeing a surging economy, it also faced protests amidst the economic impacts and inflation surge provoked by the Russian invasion of Ukraine. By mid-2023, the government had seen the resignations of 11 secretaries of state and two ministers."Terceiro Governo de Costa já teve 13 baixas em apenas 16 meses" , ECO, 7 July 2023. Retrieved 8 July 2023. The biggest scandal involved TAP Air Portugal and a compensation payment to a government member, Alexandra Reis."26 dias. Alexandra Reis durou menos tempo no Governo que Miguel Alves " , ECO, 28 December 2023. Retrieved 8 July 2023. This case was followed by a violent incident, in late April 2023, at the Ministry of Infrastructure, between government staff members and an advisor to minister João Galamba regarding an alleged stolen laptop."Acusações, ocultações, suspeitas de agressões – até houve pessoas refugiadas no WC: guia para entender a nova crise no Governo (mas dá mesmo para entendê-la?)" , CNN Portugal, 28 April 2023. Retrieved 8 July 2023. The deployment of the Portuguese Secret Services in this case stirred a clash between President Marcelo Rebelo de Sousa and Prime Minister António Costa concerning the future of Galamba and the government itself."Marcelo arrasa Galamba e promete ser mais "interventivo" e "atento" com Costa" , Diário de Notícias, 4 May 2023. Retrieved 8 July 2023.

Fall of the previous government

On 7 November 2023, the Public Security Police and the Public Prosecutor's office carried out a series of searches at the official residence of the Prime Minister and other ministries, leading to the arrest of the Prime Minister's chief of staff. Costa was named as a suspect in a corruption case involving the awarding of contracts for the lithium and hydrogen businesses, but denied any wrongdoing. He met President Marcelo Rebelo de Sousa in the Presidential Palace and announced his resignation shortly after, stating that he would not run for re-election.

The President heard all parties after Costa's resignation. The Socialist Party proposed a new cabinet led by President of the Assembly of the Republic Augusto Santos Silva, Governor of the Bank of Portugal Mário Centeno or by former minister António Vitorino, that would last until the end of the government's term in 2026, while all opposition parties, except PAN, supported an early election. The President has the power to dissolve the Assembly of the Republic at his discretion; he is not required to do so when a prime minister resigns. President Marcelo Rebelo de Sousa, after meeting with the Council of State, dissolved the assembly and called an early election.

The Prime Minister's resignation was not made official immediately; it was postponed until 8 December 2023, so that the State Budget for 2024 could be approved by parliament. It was the first time a single party majority government did not complete its full term in democratic Portugal.

Date According to the Portuguese Constitution, an election must be called between 14 September and 14 October of the year that the legislature ends. The election is called by the President of Portugal but is not called at the request of the Prime Minister; however, the President must listen to all of the parties represented in Parliament and the election date must be announced at least 60 days before the election. If an election is called during an ongoing legislature (dissolution of parliament) it must be held at least after 55 days. Election day is the same in all multi-seat constituencies, and should fall on a Sunday or national holiday. In normal circumstances, the next legislative election would, therefore, have taken place no later than 11 October 2026.

On 9 November 2023, President Marcelo Rebelo de Sousa announced he would dissolve the parliament and called an early election for 10 March 2024. On 15 January 2024, the President signed the decree that officially dissolved Parliament and set the date for the elections. Campaigning officially began on 25 February and lasted for two weeks.

Leadership changes and challenges

LIVRE After the 2022 elections, Rui Tavares was elected as a single deputy from LIVRE, running in the following party's congress, held on 5 and 6 March 2022, in order to become co-spokesperson of the party, running alongside Teresa Mota, who had been a candidate for Braga in the previous election. They faced a leadership challenge from Patrícia Robalo. In the end, Rui Tavares and Teresa Mota were elected with 67% of the votes, against the 31% from Robalo: |- style="background-color:#E9E9E9" ! align="center" colspan=2 style="width: 60px"|Candidate ! align="center" style="width: 50px"|Votes ! align="center" style="width: 50px"|% |- |bgcolor=| | align=left | Teresa MotaRui Tavares | align=right | 167 | align=right | 66.8 |- |bgcolor=| | align=left | Patrícia Robalo | align=right | 78 | align=right | 31.2 |- | colspan=2 align=left | Abstention | align=right | 5 | align=right | 2.0 |- |- style="background-color:#E9E9E9" | colspan=2 style="text-align:left;" | Turnout | align=right | 250 | align=center | |- | colspan="4" align=left|Source: Official results

CDS – People's Party In the 2022 elections, the CDS – People's Party was wiped out from Parliament for the first time in 47 years of democracy."Histórico: CDS fora do Parlamento" , CNN Portugal, 31 January 2022. Retrieved 12 February 2022. CDS leader Francisco Rodrigues dos Santos resigned on election night and announced that a leadership ballot would be held and that he would not run again, despite his promise made before the legislative elections."Francisco Rodrigues dos Santos demite-se de presidente do CDS-PP" , Diário de Notícias, 31 January 2022. Retrieved February 2022. On 11 February, it was announced that a new leader would be elected in a party congress on 2 and 3 April 2022 held in Guimarães."Conselho Nacional do CDS-PP aprova antecipação do congresso para 2 e 3 de abril" , CNN Portugal, 11 February 2022. Retrieved 12 February 2022. MEP Nuno Melo, former MP Nuno Correia da Silva, 2016 leadership candidate Miguel Mattos Chaves and Bruno Filipe Costa announced they would contest the ballot."“O CDS faz falta a Portugal”, Nuno Melo oficializa candidatura à presidência do partidol" , CNN Portugal, 19 February 2022. Retrieved 20 February 2022."CDS-PP. Miguel Mattos Chaves anuncia candidatura à liderança" , CNN Portugal, 19 February 2022. Retrieved 20 February 2022."Candidato ao CDS Bruno Filipe Costa inspira-se nos conservadores britânicos " , Público, 1 April 2022. Retrieved 2 April 2022. During the congress, Bruno Filipe Costa and Nuno Correia da Silva dropped out from the race."Congresso CDS-PP. Miguel Mattos Chaves é o único adversário de Nuno Melo " , RTP, 3 April 2022. Retrieved 3 April 2022. Nuno Melo was easily elected as leader with more than 77 percent of the votes. The results were the following:

|- style="background-color:#0c68b0" ! align="center" colspan=2 style="width: 60px"|Candidate ! align="center" style="width: 50px"|Votes ! align="center" style="width: 50px"|% |- |bgcolor=| | align=left | Nuno Melo | align=right | 854 | align=right | 77.5 |- |bgcolor=| | align=left | Miguel Mattos Chaves | align=right | 104 | align=right | 9.4 |- |bgcolor=| | align=left | Others | align=right | 144 | align=right | 13.1 |- style="background-color:#E9E9E9" | colspan=2 style="text-align:left;" | Turnout | align=right | 1,102 | align=center | |- | colspan="4" align=left|Source: Observador

Social Democratic Party

After the Social Democratic Party's (PSD) defeat in the 2022 legislative election, Rui Rio announced he would call a leadership ballot to elect a new leader, adding that he would not be a candidate again."Rui Rio confirma que não se vai recandidatar à liderança do PSD" , Diário de Notícias, 3 February 2022. Retrieved 12 February 2022. The ballot was held on 28 May 2022. Luís Montenegro, former PSD parliamentary group leader (2011–2018), and Jorge Moreira da Silva, former Environment minister (2013–2015), were the only candidates on the ballot. Around 45,000 party members, out of more than 85,000 active members, registered to vote. Montenegro defeated Moreira da Silva by a landslide, becoming the 19th leader of the party. The results were as follows:

|- style="background-color:#E9E9E9" ! align="center" colspan=2 style="width: 60px"|Candidate ! align="center" style="width: 50px"|Votes ! align="center" style="width: 50px"|% |- |bgcolor=orange| | align=left | Luís Montenegro | align=right | 19,241 | align=right | 72.5 |- |bgcolor=orange| | align=left | Jorge Moreira da Silva | align=right | 7,306 | align=right | 27.5 |- | colspan=2 align=left | Blank/Invalid ballots | align=right | 437 | align=right | – |- |- style="background-color:#E9E9E9" | colspan=2 style="text-align:left;" | Turnout | align=right | 26,984 | align=right | 60.46 |- | colspan="4" align=left|Source: Official results

Portuguese Communist Party

On 5 November 2022, the Portuguese Communist Party (PCP) unexpectedly announced that Jerónimo de Sousa, party leader since 2004, was departing from the leadership for health reasons and the demands that the post requires. The party chose Paulo Raimundo, a rather unknown party cadre and member since 1994, as new leader whose nomination was confirmed in a Central Committee meeting on 12 November 2022 by unanimous vote, with one abstention, from Raimundo himself. The results were the following:

|- style="background-color:#E9E9E9" ! align="center" colspan=2 style="width: 60px"|Candidate ! align="center" style="width: 50px"|Votes ! align="center" style="width: 50px"|% |- |bgcolor=#f00| | align=left | Paulo Raimundo | align=right | 128 | align=right | 99.2 |- | colspan=2 align=left | Against | align=right | 0 | align=right | 0.0 |- | colspan=2 align=left | Abstention | align=right | 1 | align=right | 0.8 |-