The Operational Service Medal for Sierra Leone is a campaign medal established in 2000 by the Ministry of Defence of the United Kingdom for participation in the British military intervention during and after the Sierra Leone Civil War, from May 2000 to July 2002.

DEF.The reverse bears the Union Flag, surrounded by the inscription FOR OPERATIONAL SERVICE and the four major points of the compass with, between the points, four Coronets: Royal (top left), Naval (top right), Mural (Army, bottom left), and Astral (RAF, bottom right).

[2] The length of service to qualify for the medal is determined by the mission participated in:[2] The precise dates of each operation varied, but all were within the period 5 May 2000 to 31 July 2002.

[2] The medal was also awarded for service in the wider Joint Operational Area which included Senegal, Gibraltar and offshore support ships such as RFA Argus.

[2] British forces serving with United Nations peace keeping missions in Sierra Leone did not qualify for the Operational Service Medal, but instead received the United Nations Medal with the ribbon for either UNOMSIL (1 June 1998 to 30 September 1999) or UNAMSIL (from 1 October 1999).