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A tide mill is a specialist type of water mill driven by tidal rise and fall.

A dam with a sluice is created across a suitable tidal inlet, or a section of river estuary is made into a reservoir. As the tide comes in it enters the mill pond through a one way gate, this gate closes automatically when the tide begins to fall. When the tide is low enough the stored water can be released to turn a water wheel.

Tide mills are usually situated in river estuaries, away from the effects of waves but close enough to the sea to have a reasonable tidal range. These mills have existed since the Middle Ages.

Woodbridge Tide Mill, an excellent example, survives at Woodbridge, Suffolk, England. This mill, dating from 1170 and reconstructed in 1792, has been preserved and is open to the public. Its water wheel can be seen turning. The Rance estuary in France was also home to some of these mills.

Tidal mill at l'île de Bréhat.

Another example now only visible in historic documents, is the mill in the hamlet of Tide Mills, East Sussex. Eling Tide Mill in Eling, Hampshire is the only working tide mill in the United Kingdom.

For many years a newer type of tide mill has been proposed using a dam across a large river estuary. Although it represents a source of renewable energy, each proposal tends to come under local opposition because of its likely impact on coastal habitats. However one proposal which came to fruition in 1966 is the Rance barrage. Unlike historical tide mills which could only operate on an ebb tide, the Rance barrage can generate electricity on both flows of the tide or it can be used for pumped storage depending on demand.

• Watermills in the United Kingdom
• Tidal power for modern projects

• Tide Mills in England and Wales, a catalogue of tide mills by county
• Woodbridge Tide Mill
• Eling Tide Mill