First, existing research on diffusion of disperse, reactive, and ionic dyes in polymers and correlation of the rate of dyeing to the operating variables in the dyebath is reviewed. Second, to discuss the kinetic aspects of various dyeing processes, the dyeing of textiles is classified into two categories: adsorptive and reactive dyeings, and these two dyeing processes are modeled in terms of diffusion of dyes in polymers accompanied by some physicochemical interaction with the polymer substrates. The process of adsorptive dyeing was formulated on the basis of a dual-mode sorption and mobility model where the porelike region was conveniently invoked. The calculated profiles of the concentration of immobilized dye are similar to the measurments of dye distribution curves by means of film-roll, microdensitometric, and microspectrophotometric techniques. The outline of formulation of the process of dyeing with reative dyes (i.e., reactive dyeing) is given on the basis of diffusion of dye within the fiber accompanied by a fixation reaction incorporating hydrolysis of dye species. It is concluded from numerical analysis that the lower the bath ratio, the less the decrease of the final fixation due to hydrolysis of the dye and the less the influence of mixing in the dyebath on the fixation. When the fixation reaction is slow, the final futation is almost independent of the bath ratio and the degree of mixing.