António Costa Pedro Nuno Santos The 2023 Portuguese Socialist Party leadership election was held on 15 and 16 December 2023.

[1] The leadership ballot was called after Prime Minister and Socialist Party Secretary-General António Costa resigned from office on 7 November 2023.

The declared candidates included the former Infrastructure and Housing Minister Pedro Nuno Santos, who represented the leftist faction of the party and wants to build upon the legacy of António Costa, Internal Administration Minister José Luís Carneiro, who represented the moderate faction and a continuation of Costism, and Daniel Adrião, a longtime critic of Costa as Secretary-General, who represented a rupture.

Even with the candidates claiming the contrary, this leadership election was viewed as another ideological dispute to decide what direction the party and the country should take, similar to the leadership elections of 2014 between Costa and António José Seguro, of 2004 between José Sócrates and Manuel Alegre and of 1992 between António Guterres and Jorge Sampaio.

With a turnout rate of around 70%, Pedro Nuno Santos was elected as the new Secretary-General of the Socialist Party with almost 61% of the votes, against the 37% of José Luís Carneiro.