A comprehensive concept for friction mechanisms of coated surfaces is presented. The friction mechanisms are first classified broadly into macromechanical, micromechanical, tribomechanical and material mechanisms. The macromechanical mechanisms are classified on the basis of hardness relationships between coating, substrate and counterface, the film thickness, the surface roughness and the debris in the contact. The macromechanical mechanisms are studied on the basis of shear, fracture, elasticity and rolling effects. The tribochemical mechanisms include the formation of microfilms on asperity peaks of hard coatings and the oxidation of soft coatings. The mechanisms of material transfer influences friction by changing the properties of the counterface as a transferred film is formed on it.