West Yorkshire is a metropolitan and ceremonial county in the Yorkshire and the Humber region of England. It is an inland and upland county having eastward-draining valleys while taking in the moors of the Pennines. West Yorkshire came into existence as a metropolitan county in 1974 after the reorganisation of the Local Government Act 1972 which saw it formed from a large part of the West Riding of Yorkshire. The county had a population of 2.3 million in the 2011 census making it the fourth-largest by population in England. The largest towns are Huddersfield, Castleford, Batley, Bingley, Pontefract, Halifax, Brighouse, Keighley, Pudsey, Morley and Dewsbury. The three cities of West Yorkshire are Bradford, Leeds and Wakefield.

West Yorkshire consists of five metropolitan boroughs (City of Bradford, Calderdale, Kirklees, City of Leeds and City of Wakefield); it is bordered by the counties of Derbyshire to the south, Greater Manchester to the south-west, Lancashire to the west and north-west, North Yorkshire to the north and east, South Yorkshire to the south and south-east.

Remnants of strong coal, wool and iron ore industries remain in the county, having attracted people over the centuries, and this can be seen in the buildings and architecture. Quite a few railways and the M1, M621, M606, A1(M) and M62 motorways traverse the county.

West Yorkshire includes the West Yorkshire Built-up Area, which is the biggest and most built-up urban area within the historic county boundaries of Yorkshire.