This research explores the radiological shielding performance of hybrid composites made from aramid and linen fabrics embedded in an epoxy polymer matrix, reinforced with bismuth oxide (Bi2O3), using Monte Carlo N-Particle (MCNP) simulations. The study aims to assess gamma radiation attenuation by analyzing photon flux across composite layers and energy deposition within the material. The MCNP code was utilized to simulate gamma photon interactions, investigating the effects of Bi2O3 concentration, layer thickness, and fabric arrangement. Bi2O3, known for its high atomic number and density, significantly enhances the composite’s radiation attenuation capabilities while maintaining structural integrity. The results indicate substantial reductions in photon flux and efficient energy absorption, driven by the combined properties of aramid’s mechanical strength, linen’s eco-friendliness, and Bi2O3’s superior radiation-blocking capacity. The simulations highlight how composite design influences shielding effectiveness, providing valuable insights into developing lightweight, durable materials for radiological protection in medical imaging, aerospace, and industrial applications. This work lays the groundwork for experimental validation and optimization of Bi2O3-reinforced hybrid composites, advancing the development of sustainable, high-performance solutions for radiation shielding and contributing to safer and more efficient protective technologies.