The National Security Department (國家安全處) is a specialized unit within the Hong Kong Police Force established to enforce the Hong Kong National Security Law. According to a Hong Kong government announcement made when the law was gazetted, police would establish the department on July 1, 2020, the day after the law took effect. The department is led by a Deputy Commissioner of Police for National Security, a position outside the force’s ordinary operations and management command structure, and works alongside the central government’s Office for Safeguarding National Security in Hong Kong. Its official mandate, as described by the police force, includes collecting and analyzing national security intelligence, investigating offenses that endanger national security, conducting counter-interference investigations and national security reviews, and carrying out tasks assigned by the territory’s Committee for Safeguarding National Security. The department has also organized national security-themed youth media competitions, including NStudio and NStory, and its officers have appeared as featured guests in Security Bureau-produced media content such as the television series NS Files: Decoded.