The waste of olive pomace (OP) particle filler was incorporated with glass fiber-reinforced composites (GFRP)/epoxy resin to manufacture OP particles-modified GFRP composites. Different weight ratios (0.5, 1, 2, 5, 10, and 15 wt%) of OP particles were incorporated within the common matrix of epoxy resin to investigate the effects of OP particles on tensile, flexural, and vibration damping properties on GFRP composites. In the mechanical tests, addition of OP filler contributed the significantly enhancement in tensile and flexural modulus, and samples at 5 wt% of OP filler showed highest flexural and tensile strength, while further addition of OP filler resulted in reduction of maximum elongation value at breaking point. In dynamic tests, it was found that damping ratios of the OP particles included samples were improved by 70% at OP content of 10 wt%, while first-mode natural frequency was reached optimum value at 5 wt% of OP particles, indicating better chemical compatibility at this weight content, and further incorporation of OP particles into the epoxy resin resulted in reduction for both of mechanical and dynamic properties as a result of particle aggregation effects between OP particles-epoxy resin-fiber interfaces.