The effects of 3-aminopropyl triethoxysilane (APTS) coupling agent and poly(ethylene-co-glycidyl methacrylate) (EGMA) copolymer on thermal, mechanical, and morphological properties of hybrid composites were investigated. There were a range of methods used to fabricate hybrid composites that included, untreated jute and bamboo fiber, APTS treated jute and bamboo fiber, and EGMA and low-density polyethylene (LDPE). The hybrid composites were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). In addition, tensile strength, tensile modulus, surface morphology, and water absorption tests were also reported. The IR spectra of treated jutebamboo hybrid composite revealed effective removal of OH groups from cellulose fiber using APTS. Treated jute-bamboo/polyethylene composite (TJBC) and treated jute-bamboo/EGMA/polyethylene composite (TJBEC) demonstrate 3.8 times and 3.7 times higher activation energy, respectively. High activation energy implied that APTS coupling effect is dominant compared with EGMA copolymer. A marginal decrease in the crystallinity index (15.9%) was found in case of TJBC. The tensile strength and Young's modulus of the treated hybrid composites exceeded 150% and 330%, respectively. Low water absorption rate in the treated hybrid composites was also observed. Based on the routes chosen to treat the hybrid composites along with the outcomes of the tests conducted on these suitable for the nonstructural application, such as, packaging, site hoarding, furniture, industrial shelving, and lining for truck/ van cargoes. K E Y W O R D S copolymer, coupling agent, hybrid composite, mechanical properties, thermal properties 1 | INTRODUCTION Natural fibers, derived from renewable sources, exhibit many advantages over the synthetic fibers, such as, low density, low cost, easy processing, excellent specific strength, high specific modulus, and others. 1-4 Natural fiber composites offer more alternatives in the material market due to their unique advantages, such as, high