Abstract The petroleum system is that series of interrelated processes by which hydrocarbons are generated and migrate to reservoirs from which they can be extracted commercially. The complex geology of the Gulf of Cadiz provides three separate heat sources for thermal maturation, while energetic downslope movement of crustal blocks has created reservoirs and traps that result from both structure and stratigraphic complexity. Westward extension by continental margin collapse of the Alboran Sea microplate in the Early Neogene has initiated large slump-block movements along the Iberic and Moroccan continental margins. Extensive allochthonous Late Cretaceous-Paleogene salt, deposited in a paleobasin having a western limit of 10°W to 12°W may underlie the slump-blocks at depths from 20 to 25 km and temperatures from 450° to 600°C, assuming 25°C/km gradient, and could serve as a lubricant for gravity-driven translation. Overall movement may exceed 400 km. The migrating blocks, operating as thin-skinned tectonics, and associated down-dip debris flows may be trapping mechanisms for hydrocarbons. Migrating debris covers an area as great as 90,000 km2, an area approximately equivalent to that covered by salt in the Gulf of Mexico. The eastern terminus of the Azores triple junction is well marked by shallow earthquakes (<45 km and many <30 km deep). The junction passes beneath the Gulf of Cadiz and its continental margin. Major igneous extrusions, resulting in seamount growth especially during the upper Neogene, characterize much of the bathymetrically complex Azores-Gibraltar deformation zone. The prograding Iberic and Moroccan continental rise and slope bury the tectonically active and potentially warm oceanic crust. In summary, tectonics as denoted by earthquakes within the crust (oceanic, transitional, and continental) indicates that heat is being generated and is migrating upward. Hot, upthrust basement blocks and normal sedimentary compaction thus may warm the petroleum system, and heat is transported along the salt wedges/layers and diapirs; salt is from two to three times as heat conductive as sandy clay sediment. In their often-interrupted upward migration, hydrocarbons may be stored beneath the thrusted crustal blocks. The specifics of this crustal tectonics have not been deciphered; deeper seismic penetration is needed. The possibility that the Gulf of Cadiz could contain abundant hydrocarbons is discussed. The potential oil and gas reserves may rival the size of those in the subsalt play if source rocks, maturation processes, migration routes, and reservoir systems are found to occur. At present, some 180,000 to 360,000 km3 of sediments 2 to 4 km thick in the Gulf of Cadiz have never been explored by drilling.