25th (County of London) Cyclist Battalion was a bicycle battalion of the London Regiment of the British Army. The battalion was converted to a unit of the Royal Corps of Signals in 1922.
The unit was originally formed on 26 February 1888 as the 26th Middlesex (Cyclist) Volunteer Corps, as part of a growing interest in the use of bicycles for military uses. It originally comprised three troops lettered 'A' to 'C' and was originally linked to the King's Royal Rifle Corps. It was attached to the Inns of Court Regiment and was affiliated with the Rifle Brigade (The Prince Consort's Own).
In 1908 on the formation of the Territorial Force as part of the Haldane Reforms the unit became part of the newly created London Regiment.
Men from the unit took part in the early stages of the Waziristan campaign (1919), and in the Third Anglo-Afghan War and some were present at the Amritsar Massacre in April 1919.
The battalion was transported back from India on H.M. Troopship Brandenburg in October 1919.
Its First World War memorial is located in All Saints Church, Fulham.