Valeira Dam (Portuguese: Barragem da Valeira) is a concrete gravity dam on the Douro, where the river forms the border line between the districts of Viseu and Bragança.

It is located in the municipality São João da Pesqueira, in Viseu District, Portugal.

The spillway with 5 radial gates is part of the dam body (maximum discharge 18,000 m3/s).

The run-of-the-river hydroelectric power plant was commissioned in 1976[2][3][4] (1975).

[4] The turbines were provided by Kværner, the generators by Brown, Boveri & Cie.[5] On the left side of the dam is a lock, which can handle ships with the following maximum properties: 83 m in length, 11.40 m on the beam, 3.8 m load-draught and a cargo capacity of 2500 tons.