This is probably the first report on developing nitrile butadiene rubber (NBR) composites with enhanced performances via lignin bridged epoxy resin in the rubber matrix. NBR/lignin masterbatch has been prepared through latex-compounding method, and then epoxy resin (F51) was added in the NBR/lignin compounds by the melt compounding method. Lignin-epoxy resin networks were synthesized in situ during the curing process of rubber compounds through epoxide−hydroxyl reactions. Compared with lignin filler, lignin-F51 networks showed an improved oil resistance ability and led to increased mechanical properties, crosslinking density, and thermal stability of the rubber composites. This method provides a new insight into the fabrication of novel interpenetrating polymer networks in rubber composites and enlarges the potential applications of lignin in high performance rubber composites.