AbstractThis review concerns the application of disperse dyes to poly(ethylene terephthalate) fibres using aqueous immersion dyeing processes and the roles of both elevated dyeing temperatures and carriers in the dyeing system. The precise reasons why very high temperatures in the region of 130°C promote the uptake of disperse dyes on poly(ethylene terephthalate) fibres from aqueous dyebaths have not been satisfactorily resolved, nor has the exact mechanism by which carriers promote dye uptake at lower temperatures in the region of 98°C been adequately established. In this part of the review series, a detailed review and analysis is presented of the various concepts and theories that have been proposed to account for the promotional effects of temperature and carriers on disperse dye uptake, from the viewpoint of both the thermodynamic and kinetic aspects of the adsorption of the dyes on poly(ethylene terephthalate) and other types of fibre.