Ring dyeing is a type of dyeing fault in which dyes are partially diffused to the interior of fibre.^[1] Most dyes are stained on to the fibre surface that form layer of dyes on to fibre surface. Thus around the fibre a ring-like appearance of the dye can be viewed cross-sectionally. This ring-like dye layer opposes further dye diffusion. This problem leads to poor wash fastness and rubbing fastness of dyed fabric, as well as other staining-related fastness properties.

The dye particles are not penetrated uniformly throughout the fibre structure due to several reasons like poor pre-treatment of yarn before dyeing, channeling of dye liquor circulation due to faulty loading of carriers with yarn wound packages, high density of packages (especially in cheese/cone dyeing) and many more.