| Agency Name: | Security Information Service |
| Nativename: | Serviço de Informações de Segurança |
| Type: | State Security Agency & Intelligence Agency (Internal and External Operations) |
| Formed: | 1984 |
| Headquarters: | Lisbon |
| Minister1 Name: | Luís Montenegro |
| Minister1 Pfo: | Prime Minister |
| Chief1 Name: | Adélio Neiva da Cruz |
| Chief1 Position: | Director of the SIS |
| Agency Type: | Intelligence service |
| Parent Agency: | Sistema de Informações da República Portuguesa (SIRP) |
| Website: | www.sis.pt |
The Serviço de Informações de Segurança or SIS (Portuguese for: Security Information Service) is the Portuguese security agency and intelligence agency founded in 1984 that specialized in clandestine and covert operation, counterintelligence, counterterrorism, cybersecurity, HUMINT, intelligence assessment, and SIGINT.[1]
The function of SIS is to guarantee the internal security and prevent assassination of a high-ranking official, cyber attacks, espionage, insurgency, sabotage, terrorism, and the practice of acts which, by their nature, can change or destroy the Rule of Law as constitutionally established.[2]