171st Brigade was a 2nd-Line infantry formation of the British Territorial Force raised during the First World War that served on the Western Front. The brigade's number was also used for deception purposes during the Second World War.

The 5th Battalion, King's Regiment (Liverpool) was a volunteer unit of the King's Regiment (Liverpool) of the British Army. It traced its heritage to the raising in 1859 of a number rifle volunteer corps in Liverpool, which were soon consolidated into the 1st Lancashire Rifle Volunteer Corps (RVC). It was affiliated to the King's Regiment (Liverpool), and became its 1st Volunteer Battalion of the regiment. In 1908 the battalion was transferred to the new Territorial Force as the 5th Battalion, King's Regiment (Liverpool). It saw active service on the Western Front during World War I, as did its second line second-line battalion, and even a garrison battalion. Before World War II it again formed a second line battalion. Both served in home defence, but the 5th King's landed in Normandy on D Day as part of a specialist beach group 1939. When the Territorial Army was reduced in 1967, the 5th King's became a company of the Lancastrian Volunteers.