The Cabinet Secretariat (IAST: Mantrimanḍala Sacivālaya) is responsible for the administration of the Government of India. It provides secretarial assistance to the Cabinet of India and facilitates smooth transaction of business between Ministries and Departments of the Government. Since its creation, it has functioned from the Rashtrapati Bhavan on Raisina Hill in New Delhi. But, in September 2025, the office got its independent building named Seva Teerth-2 in the Executive Enclave, that was developed under the Central Vista Redevelopment Project.

The Cabinet Secretariat is under the charge of the Prime Minister of India and is headed by the Cabinet Secretary.

During the British Raj, government business was disposed of by the Council of the Governor General of India. The council functioned as a Joint Consultative Board. The Governor-General of India's secretary was designated Secretary to the Executive Council. With the Interim Government of India being formed in 1946, the Secretariat of the Executive Council was designated as Cabinet Secretariat and the Secretary to the Executive Council re-designated Cabinet Secretary.

The Cabinet Secretariat is responsible for the administration of the Government of India (Transaction of Business) Rules, 1961 and the Government of India (Allocation of Business) Rules 1961, facilitating a smooth transaction of business in Ministries/ Departments of the Government by ensuring adherence to these rules. The Secretariat assists in decision-making in Government by ensuring Inter-Ministerial coordination, ironing out differences amongst Ministries/ Departments and evolving consensus through the instrumentality of the standing/ad hoc Committees of Secretaries. Through this mechanism new policy initiatives are also promoted.

Cabinet Secretariat is organised as follows: Secretary (Coordination), Secretary (Security) (under whom comes the Special Protection Group) and Secretary (R) (heads Research and Analysis Wing;). Chairperson (National Authority for Chemical Weapons Convention), NIC Cell, The Directorate of Public Grievances, Direct Benefits Transfer (DBT) Mission, Vigilance & Complaints Cell (VCC) is also under the Cabinet Secretariat.

The Cabinet Secretary is the ex-officio head of the Civil Services Board, the Cabinet Secretariat, the Indian Administrative Service (IAS) and head of all civil services under the rules of business of the Government.

The Cabinet Secretary is generally the senior-most officer of the Indian Administrative Service. The Cabinet Secretary ranks 11th on the Indian Order of Precedence. The Cabinet Secretary is under the direct charge of the prime minister. Though there is no fixed tenure, the office-bearer's tenure can be extended.

Before the adoption of the portfolio system in the Government of India, all governmental business was disposed of by the Governor-General-in Council (earlier name of Cabinet Secretariat), the Council functioning as a joint consultative board. As the amount and complexity of business of the Government increased, the work of the various departments was distributed amongst the members of the council: only the more important cases were dealt with by the Governor-General or the Council collectively.