The River Medina is the main river of the Isle of Wight, England, rising at St Catherine's Down near Chale, and flowing northwards through the county town Newport, towards the Solent at Cowes. The river is a navigable tidal estuary from Newport northwards, where it takes the form of a ria (a drowned valley). This occurred because the Medina used to be a tributary of what was once the "River Solent", with a larger catchment area. As the Solent valley flooded, the river received less water and more sediment, causing it to become more tidal.
The river is bridged at Newport. Cowes is connected to East Cowes by a chain ferry known as the Cowes Floating Bridge. The river also has several small ferries which cater mainly for sailors.