Epoxy is a hard, brittle but strong polymeric material and various types of research works are being carried out to exploit its unique properties in commercial service particularly as composite materials. One of these researches is to study the effect of addition of Thal silica sand nanoparticles and glass fiber on epoxy-based hybrid composites. The silica sand was collected from Thal desert situated in Punjab province of Pakistan, milled to nanoparticles using a ball mill. The production of silica sand nanoparticles was verified using a Zeta sizer nanoparticles analyzer and SEM analysis. These silica sand nanoparticles were utilized to develop the epoxy-based composites. The glass fibers were cut into small pieces of 2 cm in length and thoroughly mixed with epoxy along with silica sand nanoparticles. Hand-lay-up fabrication technique was proceeded by room temperature curing which was used to develop the epoxy-based hybrid composites. The tensile and impact specimens were made according to ASTM standard and tested using universal tensile testing and charpy impact testing machines. A Vickers hardness tester, applying 50 g load for 10 s, was used to determine the hardness of the composites. The thermo-gravimetric analysis was carried out to analyze the thermal behavior of the composites particularly to evaluate mass loss or gain due to decomposition and oxidation using TGA apparatus. The interaction of glass fiber and silica sand nanoparticles with epoxy was studied using scanning electron microscopy. It was observed that with increasing silica sand nanoparticles and glass fiber contents, the hardness, tensile, and impact properties of the epoxy-based hybrid composites increased. The TGA results showed that the developed hybrid composites became stable at 300 °C. © 2014, Iran Polymer and Petrochemical Institute.