The development of bio-based epoxy resins from renewable feedstocks are significantly in high demand as a sustainable alternative to petroleum-derived polymers. In this study, lignin extracted from different sources, specifically spruce and oat husk, was utilized in both its non-fractionated and in different fractions/depolymerized forms. These lignin variants were chemically modified through epoxidation using epichlorohydrin under alkaline conditions to introduce reactive epoxy functional groups, thereby enhancing its compatibility with conventional epoxy resin systems. The structural modifications and molecular weight distribution of the epoxidized lignin were characterized using ¹H NMR, FTIR, and GPC [1,2,3}. The incorporation of epoxidized lignin forms can result in improved impact resistance and comparable thermal stability, demonstrating its potential as a partial replacement for fossil-based epoxy components. This study will highlight the feasibility of utilizing lignin from various sources and processing methods as a valuable precursor for high-performance bio-based epoxy resins, contributing to sustainable material innovation.