Relleu is a municipality in the comarca of Marina Baixa, in the province of Alicante, within the Valencian Community of Spain. It is one of the inland towns of the Marina Baixa, a coastal comarca whose administrative centre and best-known resort is Benidorm.
The town sits in the mountainous interior behind the Alicante coastline, at an elevation well above the coastal plain. Its setting among terraced slopes and surrounding sierra has long been associated with almond and olive cultivation, and the older part of the village retains narrow, steep streets and whitewashed houses typical of the region.
Relleu is reached by road from the coast via the neighbouring municipalities of Villajoyosa and Orxeta, and it remains a small, predominantly residential settlement rather than a resort destination.