Castor oil-based epoxy monomer was prepared using a two-step approach: epoxidation of castor oil, followed by acrylation of epoxidized castor oil. A bio-based diglycidyl ether of bisphenol A (DGEBA) epoxy nanocomposites was prepared by the incorporation of organo-modified montmorillonite (OMMT) clay to the DGEBA/AECO system. The cured bio-based DGEBA epoxy nanocomposites at 0.80:0.2:0.001 g/g exhibited higher tensile strength (56 MPa), tensile modulus (1933 MPa), flexural strength (132 MPa), flexural modulus (2518 MPa), elongation (23.1 %), and impact strength (34 kJ/m(2)). The nanocomposites at 0.6:0.4:0.001 g/g can easily bend up to 360 degrees without any damage; similarly, the 0.8:0.2: 0.001 g/g system can bend up to 180 degrees. Thermal behaviour of the bio-based epoxy systems was characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The obtained nanocomposites displayed a higher char yield (8.9 %) at 700 degrees C and glass transition temperature (108 degrees C) than the DGEBA/AECO systems. Further SEM analysis was used to study the morphological changes in the fractured surfaces of bio-based epoxy systems, which reveals that crack propagation decreases with addition of AECO to the DGEBA epoxy system.