The secretary of state for Commonwealth relations was a secretary of state in the Government of the United Kingdom, responsible for dealing with the United Kingdom's relations with members of the Commonwealth of Nations (its former colonies). The minister's department was the Commonwealth Relations Office (CRO).
The position was created in 1947 out of the old positions of secretary of state for dominion affairs and secretary of state for India. In 1966, the position was merged with that of the secretary of state for the colonies to form that of secretary of state for Commonwealth affairs, which was in turn merged with the secretary of state for foreign affairs in 1968 to create the new position of secretary of state for foreign and Commonwealth affairs. The equivalent position today is the secretary of state for foreign, Commonwealth and development affairs.