Segurança Social is Portugal's public social security system, responsible for administering pensions, unemployment benefits, sickness pay, parental leave, family allowances, and other social support payments. It is funded through mandatory contributions from employers and employees.

Most services are managed online through Segurança Social Direta (SSD), where users can check contribution records, apply for benefits, submit declarations, and track payments using their NISS (Social Security Identification Number) and Citizen Card credentials.

Key interactions for residents include registering as a contributor (mandatory for all workers), claiming unemployment benefits, applying for parental leave, and accessing the minimum income scheme (Rendimento Social de Inserção). Self-employed workers (trabalhadores independentes) must also make quarterly income declarations through the platform.