Thwaite Mills or Thwaite Watermill is an industrial heritage site in Leeds, West Yorkshire, England, on the River Aire and the Aire and Calder Navigation. It is a fully restored working water-powered mill built in 1823-25, harnessing the power of the river, and has been called "one of the best last remaining examples of a water-powered mill in Britain". The mill, the manager's house and three associated buildings are all grade II listed buildings. The site was open to the public as a museum operated by Leeds City Council until 1 April 2024.

Leeds City Council is the local authority of the City of Leeds in West Yorkshire, England. It is a metropolitan district council, one of five in West Yorkshire and one of 36 in the metropolitan counties of England, and provides the majority of local government services in Leeds. It has the second-largest population of any council in the United Kingdom with approximately 800,000 inhabitants living within its area; only Birmingham City Council has more. Since 1 April 2014, it has been a constituent council of the West Yorkshire Combined Authority.