The aim of the project is to study the interlaminar fracture toughness, GIC of woven silk reinforced epoxy composite. Silk fibre has been treated with silane coupling agent and the silk/epoxy composites has been fabricated with different number of silk fibre layers. The processing technique used to prepare the sample is a vacuum bag cured in an autoclave. In this study, test specimens were fabricated by using silk fibre of between 8 to 14 layers. The first set of composites panel consisted of plain silk fibre while the second sets consisted of silk fibre which has been treated with 3-aminopropyl triethoxysilane. Mode I test based on double cantilever beam specimens (DCB) method have been used over all the specimens. The results of the GIC were plotted and compared. GIC of the composites in set 2 were found to be higher than the value in set 1. During the test, crack propagation is stable and no fibre bridging occurred between both sides of fracture surfaces. All the failure that occurred were at the fibre-matrix interface as seen using SEM. The GIC of woven silk/epoxy composites can be enhanced by surface treatment using coupling agent. Surface treatment and number of woven silk fibre layers has affected the interlaminar fracture properties of the composite panel.