The Home Counties Division was an infantry division of the Territorial Force, part of the British Army, that was raised in 1908. As the name suggests, the division recruited in the Home Counties, particularly Kent, Middlesex, Surrey and Sussex.

At the outbreak of the First World War, it accepted liability for overseas service and was posted to India in 1914 to relieve Regular Army units for service on the Western Front. On arrival in India it was effectively broken up, so it did not see active service as a complete formation. However, most of its constituent units did serve in active theatres, notably Mesopotamia from 1915 and in the Third Anglo-Afghan War in 1919.

Reformed in the Territorial Army (TA) in 1920 as the 44th (Home Counties) Division, the division saw active service in the Second World War in Belgium, France and North Africa (notably in the Battle of El Alamein) before again being disbanded in 1943. Once again, its component units continued to serve, in North Africa, Italy, North-West Europe, and Burma.

The division was again reformed in the TA in 1947 before being merged with the Home Counties District in 1961, thus ending its separate existence.

The Territorial Force (TF) was formed on 1 April 1908 following the enactment of the Territorial and Reserve Forces Act 1907 (7 Edw.7, c.9) which combined and re-organised the old Volunteer Force, the Honourable Artillery Company and the Yeomanry. On formation, the TF contained 14 infantry divisions and 14 mounted yeomanry brigades. One of the divisions was the Home Counties Division.

As the name suggests, the division recruited in the Home Counties, particularly Kent, Middlesex, Surrey and Sussex. It was composed of the Surrey, Middlesex and Kent Infantry Brigades (each of four battalions), four artillery brigades of the Royal Field Artillery recruited in Sussex and Kent, a heavy battery of the Royal Garrison Artillery (also recruited in Kent), plus support units of the Royal Engineers (including the Signal Service), Royal Army Medical Corps and the Army Service Corps. Two Army Troops battalions of the Royal Sussex Regiment were also attached for training, but were not integral to the division. In peacetime, the divisional headquarters was in Hounslow in Middlesex.

In accordance with the Territorial and Reserve Forces Act 1907 (7 Edw.7, c.9) which brought the Territorial Force into being, the TF was intended to be a home defence force for service during wartime and members could not be compelled to serve outside the country. However, on the outbreak of war on 4 August 1914, many members volunteered for Imperial Service. Therefore, TF units were split into 1st Line (liable for overseas service) and 2nd Line (home service for those unable or unwilling to serve overseas) units. 2nd Line units performed the home defence role, although in fact most of these were also posted abroad in due course. The Home Counties Division formed the 2nd Home Counties Division in this manner with an identical structure.

The division mobilised on the outbreak of the war. Early in September 1914, the division sent two battalions to Gibraltar to relieve regular battalions; 7th and 8th Middlesex left on 4 and 10 September respectively. On 22 September, India agreed to send 32 British and 20 Indian regular battalions to Europe in exchange for 43 partially trained TF battalions. Accordingly, the division accepted liability for service in India. It was joined by the 4th (Cumberland and Westmorland) Battalion, Border Regiment (from Carlisle) and the 4th Battalion, King's (Shropshire Light Infantry) (from Shrewsbury) to replace 7th and 8th Middlesex, and 1/1st Brecknockshire Battalion, South Wales Borderers (from Brecon) as an extra battalion for garrison duties in Aden.