The River Idle is a river in Nottinghamshire. It is formed where the River Maun meets to River Meden at Markham Moor. It then flows through Retford and Bawtry before entering the River Trent.
It is navigable from Bawtry Bridge in Bawtry to Stockwith, where it connects with the tidal River Trent. There are no locks along the 10.9 mile stretch.
Although there is no navigation authority for the river Idle, access to the river at West Stockwith is controlled by a tidal sluice gate operated by the Environment Agency.