The 2025 Portuguese Socialist Party leadership election was held on 27 and 28 June 2025 to elect a new Secretary General of the party following the defeat in the 2025 Portuguese legislative election. The election was called by Pedro Nuno Santos after achieving a disappointing third place and losing the status of leader of the opposition with him resigning and not seeking reelection.
After the Party President and acting Secretary General Carlos César declaring that the election will be held either in the last week of June or the first of July, Mariana Vieira da Silva and Fernando Medina, both highly speculated names of the Costista wing of the party to run for Secretary General, as well as Duarte Cordeiro and Alexandra Leitão, two of the closest alies of Pedro Nuno Santos and members of the left-wing faction of the party, declined to run in name of party unity and because of the short time necessary to prepare a candidacy. Because of this José Luís Carneiro, a high-profile member of the Segurista faction and Centrist wing of the party, and runner-up of the previous internal election, was expected to be the sole candidate.