The Ashley River is a river in South Carolina, rising from the Wassamassaw and Great Cypress Swamps in Western Berkeley County. It consolidates its main channel about 5 miles west of Summerville, widening into a brackish, tidal estuary just south of Fort Dorchester. The much wider Ashley joins the Cooper River in Charleston to form the Charleston Harbor before discharging into the Atlantic Ocean.

The river was named for Anthony Ashley Cooper, 1st Earl of Shaftesbury and chief Lord Proprietor of the Carolina Colony. Charleston was founded on the western bank of the Ashley in 1670 (at Charles Towne Landing), before moving across to its current peninsular location ten years later.