Liddel Water is a river running through southern Scotland and northern England, for much of its course forming the border between the two countries, and was formerly one of the boundaries of the Debatable Lands.

Soon afterwards, the nascent Liddel Water is fed by Dawston Burn near the village of Saughtree.

The river continues to pick up tributaries (listed below) as it follows its southwesterly course, which takes it through the village of Newcastleton (also known as Copshaw Holm) to that of Kershopefoot, where the burn begins to mark the Anglo-Scottish border.

Liddel Water then flows into the River Esk at Willow Pool, overlooked by the earthworks of the former castle of Liddel Strength near Carwinley, Cumbria.

This article related to a river in Scotland is a stub.