Fratel Dam (Portuguese: Barragem de Fratel) is a concrete gravity dam on the Tagus, where the river forms the border line between the districts of Castelo Branco and Portalegre.

It is located in the municipality Vila Velha de Ródão, in Castelo Branco District, Portugal.

[1] The construction of the dam meant the flooding of most of the tens of thousands of petroglyphs found in the Tagus valley rock art area.

The spillway is part of the dam body (6 radial gates with a maximum discharge capacity of 16,500 m³/s).

The power station contains 3 Kaplan turbine-generators with 45.6 MW (50 MVA) each in a dam powerhouse.