West Lothian (Scots: Wast Lowden; Scottish Gaelic: Lodainn an Iar) is one of the 32 council areas of Scotland, and was one of its historic counties. The county was called Linlithgowshire until 1925. The historic county was bounded geographically by the Avon to the west and the Almond to the east. The modern council area occupies a larger area than the historic county. It was reshaped following local government reforms in 1975: some areas in the west were transferred to Falkirk; some areas in the east were transferred to Edinburgh; and some areas that had formerly been part of Midlothian were added to West Lothian.

West Lothian lies on the southern shore of the Firth of Forth and is predominantly rural, though there were extensive coal, iron, and shale oil mining operations in the 19th and 20th centuries. These created distinctive red-spoil heaps (locally known as "bings") throughout the council area. The old county town was the royal burgh of Linlithgow, but the largest town (and the second largest town in the Lothian region after Edinburgh) is now Livingston. Other large towns in the county include Bathgate (a town with medieval origins that developed extensively during the industrial revolution) and the historic mining settlements of Armadale, Fauldhouse, Whitburn, West Calder, Uphall, and Broxburn.