Guadiaro is a neighborhood (parish) of the city of San Roque on the right bank of the Guadiaro River in the Province of Cádiz, Andalusia, Spain.

Due to its proximity to the coast and to the urbanization luxury Sotogrande, Guadiaro is mainly engaged in tourism.

Guadiaro is the archaeological site of Barbésula, an old Roman city.

The road A-2100 leads from Guadiaro to Castellar de la Frontera.

In August 2010 a roofed taxi stand entered service.