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.

[3] The biggest scandal involved TAP Air Portugal and a compensation payment to a government member, Alexandra Reis.

[4] 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.

[5] The deployment of the Portuguese Secret Services in this case stirred a clash between Marcelo Rebelo de Sousa, the incumbent president of Portugal, and Prime Minister António Costa concerning the future of Galamba and the government itself.

[7] 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.

[8] 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.

[9] The Socialist Party proposed a new cabinet led by President of the Assembly of the Republic Augusto Santos Silva,[10] Governor of the Bank of Portugal Mário Centeno[11] or by former minister António Vitorino,[12] that would last until the end of the government's term in 2026, while all opposition parties, except PAN, supported an early election.

[14] President Marcelo Rebelo de Sousa, after meeting with the Council of State, dissolved the assembly and called an early election for 10 March 2024.

[15] 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.

[20] On 9 November 2023, President Marcelo Rebelo de Sousa announced he would dissolve the parliament and called an early election for 10 March 2024.

[33] 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.

[42] A few weeks later, the party decided on a date and location for the leadership ballot – the new leader would be elected in a National Convention between 21 and 22 January 2023 in Lisbon.

[48] In a rather tense congress, with strong accusations between both sides,[49] Inês Sousa Real was re-elected party leader with 73 percent of the votes.

[54] A list of critics of the then party leadership, led by former MP Pedro Soares [pt], opposed Mortágua in the convention ballot.

Governments do not require an absolute majority support of the Assembly to hold office, as even if the number of opposition MPs is larger than that of its supporters, the opposition still needs to be equal to or greater than 116 (absolute majority) for both the Government's Programme to be rejected or for a motion of no confidence to be approved.

AD leader Luís Montenegro, initially against the idea of letting the PS govern, also changed his tone but speculation remained regarding his position.

[92] In an interview with Expresso on 8 March, President Marcelo Rebelo de Sousa said that he would do everything in his ability to prevent Chega from gaining power, which drew criticism due to his position's mandate of neutrality.

[93] In a televised address on 9 March, Rebelo de Sousa called for people to vote, citing the risk of economic problems caused by elections in the European Parliament and the United States later in the year, and the ongoing conflicts in Ukraine and the Middle East.

The country faced a housing crisis [pt] and soaring rent prices, a deteriorating public health and education system, shortages of teachers and doctors, very low wages and high inflation.

[110] The final results of the election were released late on 20 March, when the counting of overseas ballots that constitute four seats was concluded.

[111] In the closest legislative election in Portuguese history, the Democratic Alliance narrowly won, gathering 28.8 percent of the votes and winning 80 seats.

Despite the narrow margin between the Alliance and the Socialists, the PS fell 13 points and lost more than 40 seats compared with the 2022 election.

[112] On election night, leader Pedro Nuno Santos conceded defeat and said that the PS would now lead the opposition.

The CDU won four seats, a decrease of two compared with 2022, and just 3.2 percent of the votes, their worst nationwide electoral performance to date.

[127] Minister of Finance Fernando Medina, who had been considered as a possible replacement as leader of PS, said that the defeat was due to the entire party and not Santos' leadership.

[137] On 21 March, Luis Montenegro was formally asked by President Rebelo de Sousa to form a minority government[138] following the latter's consultations with party leaders.

[139] The final, certified election results were published in the Portuguese official journal, Diário da República, on 23 March 2024.

[149] Pedro Nuno Santos recognized the concessions made by the government, but pressed for more conditions on corporate tax cuts, mainly on their timing.

Though his conditions were not met, Santos justified the decision with the desire to avoid a snap election less than a year after the previous one, but stressed that the government was now "isolated" and "absolutely dependent" on the opposition.