South Yorkshire is a metropolitan county in England. It is the southernmost county in the Yorkshire and the Humber region and had a population of 1.34 million in 2011. It has an area of 1,552 square kilometres (599 sq mi) and consists of four metropolitan boroughs, Barnsley, Doncaster, Rotherham and Sheffield. South Yorkshire was created on 1 April 1974 as a result of the Local Government Act 1972 with Barnsley as its county town.

Lying on the east side of the Pennines, South Yorkshire is landlocked, and borders Derbyshire to the west and south-west, West Yorkshire to the north-west, North Yorkshire to the north, the East Riding of Yorkshire to the north-east, Lincolnshire to the east and Nottinghamshire to the south-east. The Sheffield Urban Area is the tenth most populous conurbation in the UK, and dominates the western half of South Yorkshire with over half of the county's population living within it. South Yorkshire lies within the Sheffield City Region with Barnsley also being within the Leeds City Region, reflecting its geographical position midway between Yorkshire's two largest cities.

South Yorkshire County Council was abolished in 1986 and its metropolitan boroughs are now effectively unitary authorities, although the metropolitan county continues to exist in law. As a ceremonial county, South Yorkshire has a Lord Lieutenant and a High Sheriff.

South Yorkshire was created from 32 local government districts of the West Riding of Yorkshire (the administrative county and four independent county boroughs), with small areas from Derbyshire and Nottinghamshire.