In a campaign dominated by the Tancos airbase robbery[3] (in which former Defense Minister Azeredo Lopes (2015–2018) was accused of trying to cover-up the finding of the stolen weapons in the robbery), but also with the good economic situation in Portugal, the Socialist Party (PS) won the elections with 36 percent of the votes and 108 seats, a gain of 22 compared with 2015.

The Unitary Democratic Coalition, (CDU), PCP-PEV coalition, suffered heavy losses, with 6.3 percent of the votes and 12 seats, and Jerónimo de Sousa, PCP secretary-general, said on election night that written agreements with PS were off the table.

Assunção Cristas, CDS leader, resigned on election night, called for a snap party congress and announced she would not run for reelection.

[7] People-Animals-Nature (PAN) saw a big increase in its share of the vote, winning 3.3% and 4 seats from Lisbon, Porto and Setúbal.

Former Prime Minister and PSD leader Pedro Santana Lopes' new party, Alliance, failed to win a single seat and polled below 1 percent of the votes.

[11] However, during this period, the Socialist Party, the Left Bloc and the Communist Party reached a historic agreement in order to bring down the Passos Coelho minority government and support a Socialist minority government led by António Costa.

[15] Costa's term was also marred by the 2017 deadly wildfires, in June and in October, plus the Tancos arms theft scandal, which would have an impact during the 2019 election campaign.

[19] Shortly after, Pedro Santana Lopes, former mayor of Lisbon (2002-2004; 2005) and Prime Minister (2004-2005), announced he was also running for the leadership of the party.

[21] The results were the following: Rui Rio was officially confirmed as party leader in the PSD congress, in Lisbon, between 16 and 18 February 2018.

[25] After meeting with all parties, in December 2018, Marcelo Rebelo de Sousa announced that he would call a general election for 6 October 2019.

The centre-left Socialist Party (PS) of incumbent Prime Minister Costa obtained the largest share of the vote, and the most seats.

[49] After this, budgets and other policies were discussed with all opposition parties, but political instability grew, even during the COVID-19 pandemic outbreak.

[52] On 27 October 2021, Parliament rejected the budget by a 117 to 108 vote, and a snap general election was called for 30 January 2022.