Most previous studies on Attic black gloss technology focused on productions from Greece, especially Athens. However, the black gloss technique constitutes the most widespread decoration practice across the Mediterranean from the Archaic to the Hellenistic periods. Focusing on both Attic and Atticising black gloss productions from sites in Sicily and Asia Minor, our work aims to shed new light on the technology of this decoration and its transmission throughout the Mediterranean during the fourth century BCE. Additionally, to investigate the technological relationship between black and the less common intentional red gloss decorations, a selection of bichrome black-and-red and red gloss vessels were included in this study. For this purpose, we applied an integrated analytical approach, aiming to characterise both the chemistry and the mineralogy of archaeological black and red gloss decorations. This approach includes ceramic petrography, pXRF, µ-XRD2, and SEM-EDS. Specimens from the fourth century BCE from Manfria (chora of Gela), Iasos (Caria), and Priene (Ionia) were analysed. These assemblages reflect various production groups identified by the chemical and petrographic analyses of the ceramic bodies. The µ-XRD2 and SEM-EDS measurements of the gloss show a certain degree of mineralogical and chemical variability that does not necessarily correlate with the recognised production groups but, rather, reflects different technological practices. Despite this variability, the results suggest that the various gloss productions were produced with a very similar technological process and offer new insights into the mechanisms through which the black gloss technique diffused throughout the Mediterranean.