The Imperial Secretariat Service (commonly abbreviated as the ISS) was a civil service of the British Empire in British India during British rule in the period between 1919 and 1945. The members served in the 5 central departments (1924 to 1934) and then later expanded to 10 central departments at that time, Secretariat of the Viceroy's Executive Council and later Cabinet Secretariat and Central Secretariat.
The service was one of the "Imperial Services" with the Imperial Civil Service, Indian Imperial Police, and Imperial Forest Service of the Indian Government under the British colonial rule in India.
This service still continues in the contemporary Civil Services of India, Central Superior Services of Pakistan and Bangladesh Civil Service, though these are now organised differently post-independence. It is an earliest organised civil service.