This palaeodietary study presents carbon and nitrogen stable isotope data from human and faunal skeletal remains from the Copper Age settlement of Valencina de la Concepción–Castilleja de Guzmán, located in Seville, Spain. Montelirio, the only Valencina–Castilleja human group from which we have obtained reliable palaeodietary results, had a diet based on C3 terrestrial resources, including both plants and animals. The protein component of the diet consisted mainly of meat, milk and dairy products from livestock as well as C3 plant protein from cereals and pulses. This study compares data from Montelirio, the Copper Age group from Valencina–Castilleja, with the published data from other Iberian Late Neolithic–Copper Age (LN‐CA) societies. This comparison reveals a homogeneous diet with some exceptions. Overall, the LN‐CA diet in the Iberian Peninsula consisted mainly of animal proteins from meat, milk and dairy products from livestock as well as C3 plant sources from the characteristic agriculture of the societies of these periods. This study also demonstrates the minor use of aquatic resources from the Neolithic to the Copper Age period in the Iberian Peninsula. Copyright © 2015 John Wiley & Sons, Ltd.