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A review is given on transport and equilibrium sorption of moisture in polymer films and organic coatings. Polymeric material forms the continuous phase of a coating and is therefore important for transport properties. Besides polymer, coatings consist of pigments and fillers and various additives, each of them affecting moisture transport. Firstly, in this paper typical transport and equilibrium characteristics of pure polymer films are covered, and secondly those of coatings, assimilating the impact of pigments, fillers and additives. Discrimination between Fickian and non-Fickian effects is usually based on the appearance of kinetic absorption curves. Several types of curve are dealt with, and models that describe these curves are discussed. These include “two-stage” sorption, “sigmoidal” sorption and “Case II” sorption. The common practice of fitting Fick’s law to kinetic data by means of relaxation parameters is criticized …