The Assistant Chief of the Defence Staff (ACDS) is a senior British military officer.
There are a number of ACDS appointments and they are held by officers of two-star rank (rear admiral, air vice-marshal, or major general).
Since 1992, the Defence Services Secretary has usually holds the appointment of ACDS(P) as a secondary role.
The ACDS(R&C) is the senior reservist of the British Armed Forces.
They are responsible for tri-service policy relating to the reserves and cadet forces.