Sian Christina MacLeod OBE (born 31 May 1962) is a British diplomat who was formerly head of the UK delegation to the Organization for Security and Co-operation in Europe (OSCE) in Vienna.

[1] MacLeod graduated from the Royal Academy of Music with a BMus degree in 1983.

After the collapse of the Soviet Union she served briefly as deputy head of mission in Vilnius, Lithuania, in 1992.

She was sent back to Moscow 2004–07, first as political counsellor and then as minister and deputy head of mission.

[4] MacLeod was appointed OBE in 2002 "in recognition of services in support of operations in Afghanistan during the period 1st October 2001 to 31st March 2002".