The archaeological excavation of ‘Piazza Bovio’ at Naples has yielded a large deposit, characterized by exceptional findings relating to the production of a glass workshop dated to the sixth to seventh centuries ad. The workshop features, coupled with the presence of broken glass for recycling and abundant glass scrap, leads us to identify the area as part of a secondary workshop. Selected finished objects and glass scraps were characterized by SEM/EDS and LA–ICP–MS and compared with major compositional groups of glass recognized in the western Mediterranean during the first millennium ad. The aim is to verify the hypothesis of a secondary production in Naples, using raw glass from the Levant area. Three different natron groups were identified on the basis of the colour and the chemical composition. The naturally coloured (blue–green) group is consistent with Levantine I glass. The yellow–green group is associated with HIMT glass, while the colourless glass was produced with different raw materials and probably in another specialized workshop.