The Baetican Dressel 20 is probably the most widely diffused amphora of the Roman period, found in large quantities throughout all the Roman and nearby territories. It is the most powerful evidence of the importance of the olive oil trade for Roman society and of olive oil's extraordinary production in the Baetican countryside. This wide diffusion of the amphora and, in some ways, its ubiquity at many archaeological sites, have hindered the study of the early stages of Baetican olive oil production and diffusion. The protagonists were not these spherical containers, commonly stamped up until the late 3rd c. CE, but previous models that evolved rapidly after their origins in Late Republican times. In this paper, we aim to analyze not only the formal characteristics and evolution of these peculiar and still unstandardized containers, but also other aspects linked to their production, as well as the scope of their diffusion.