The canals of the United Kingdom are a major part of the network of inland waterways in the United Kingdom. They have a varied history, from use for irrigation and transport, through becoming the focus of the Industrial Revolution, to today's role of recreational boating. Despite a period of abandonment, today the canal system in the United Kingdom is again increasing in use, with abandoned and derelict canals being reopened, and the construction of some new routes. Canals in England and Wales are maintained by navigation authorities. The biggest navigation authorities are the Canal & River Trust and the Environment Agency, but other canals are managed by companies, local authorities or charitable trusts.

The majority of canals in the United Kingdom can accommodate boats with a length of between 55 and 72 feet (17 and 22 m) and are now used primarily for leisure. There are a number of canals which are far larger than this, including New Junction Canal and the Gloucester and Sharpness Canal, which can accommodate boats with a length of up to 230 feet (70 m). An incomparable purpose-built ship canal is the Manchester Ship Canal. Upon opening in 1894, it was the largest ship canal in the world, permitting ships with a length of up to 600 feet (183 m) to navigate its 36-mile (58 km) route.