Socialist Party (PS)

• Leader: José Luís Carneiro (since June 2025)
• Ideology: Center-left, Social democracy, pro-Europeanism

Portugal's other traditional major party suffered a historic collapse in the 2025 election, dropping from 78 to 58 seats and falling to third place for the first time in democratic history. The party was led by Pedro Nuno Santos from January 2024 until his resignation following the May 2025 defeat. José Luís Carneiro, a 53-year-old former Minister of Internal Administration known for his moderate positioning within the party, was elected unopposed as the new Secretary-General with 95% of votes in June 2025. ​ The Socialist Party governed Portugal from 2015 to 2024, including an absolute majority from 2022 to 2024 under António Costa, who resigned in November 2023 amid a corruption investigation. The PS previously led the innovative "Geringonça" (contraption) coalition government from 2015-2019, a minority government supported by the Left Bloc and Portuguese Communist Party that reversed austerity measures and presided over economic recovery.