Composites reinforced with natural plant fibers are currently actively researched. Inverse gas chromatography (IGC) is a technique that is used to characterize the surface energy and polar characteristics of materials. The theoretical approaches used with IGC are reviewed and applied to the Study of 14 ligno-cellulosic fiber types including grass fibers, bast fibers, leaf fibers, seed fibers, and fruit fibers. This was done to provide insight into the impact of fiber composition on the surface characteristics of the different fiber types and explore possible correlations among the data. The dispersive surface energy, and K-a, K-b, constants are reported for the 14 fiber types and compared with values reported in the literature. The dispersive energies ranged from 35.5 mJ/m(2) to 44.2 mJ/m(2) at 20 degrees C with K-a from 0.01 to 0.38 and K-b from 0 to 1.05. A correlation was found at 40 degrees C for surface energy related to fiber composition and fiber type where the surface energy decreases with increasing lignin and hemicellulose composition but increased with increasing cellulose concentration. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 3880-3888,2008