In this work banana fibre was chemically modified using various chemical agents. The surface energy of the fibre is an important parameter and one which governs the interaction of fibre with polymeric matrices. This paper describes the influence of various chemical treatments on the surface energy of the banana fibre investigated by contact angle measurements, spectroscopic analysis and surface morphology studies. The surface energy, work of adhesion, polarity, spreading coefficient, interfacial energy and interaction parameter were determined in the case of raw and chemically modified fibres. Chemical modification has been found to have a profound effect on the surface energy. The polar and dispersive components of the surface energy were also found to be dependent on the chemical treatment involved. The chemical modifications done in this work were: alkali treatment, silanation, benzoylation, formylation, potassium permanganate treatment and acetylation. Of all the modifications, the relative surface energy was found to be a maximum for alkali treated fibre and minimum for silanated fibre. Contact angle measurements were found to be an effective tool in predicting the possible interaction of the fibres with phenol formaldehyde matrix resin. Atomic force microscopy roughness analysis revealed a significant decrease in surface roughness for the chemically modified fibre. An increase both in fibre/matrix adhesion and interfacial shear strength has been observed for all surface modified fibres except for those modified by benzoylation and acetylation. (C) Koninklijke Brill NV, Leiden, 2011