Breña Baja (Spanish for Lower Breña) is a municipality on the eastern side of the island of La Palma in the Canary Islands. The ayuntamiento (municipal office) is in the town of San José with an elevation of 300 m. Until the 17th century the area was known as Breña, but was then divided into Breña Alta and Breña Baja.

La Palma's second largest resort, Los Cancajos, is on the coast. Part of La Palma Airport (formerly Mazo Airport) is located in the municipality.