Acid, metal complex, afterchrome, and reactive dyestuffs were used to investigate the influence of dyeing on the chemical and physical properties in general, and the felting properties in particular, of wool. A morphology of wool, a theoretical interpretation of the felting process, and a description of the dyes used accompany a discussion of the study. Results showed that 1:1 and 1:2 metal complex dyestuffs and afterchrome dyestuffs had a strong influence on felting properties. Wool tops dyed with afterchrome dyestuffs showed a decrease in feltability.