Central Secretariat Service is the administrative civil service under Group A and Group B of the Central Civil Services of the executive branch of the Government of India. They are governed by Central Secretariat Service Rules of 1962, which has been issued under the powers of Article 309 of the Constitution of India. The service members work under restrictions and rules of Central Civil Services (Conduct) Rules.

In India, the Civil Service is the collection of civil servants of the government who constitute the permanent executive branch of the country. This includes servants in the All India Services, the Central Civil Services, and various State Civil Services, who are recruited by the Union Public Service Commission (UPSC), the Staff Selection Commission (SSC), and each state's Public Service Commissions.