In this study, solid particle erosion behaviour of glass fibre mat-based polyester laminate composite materials was investigated by varying the impact velocity and the impingement angle and sizes of the abrasive particles. Impact velocities used in the tests were 23, 34 and 53m/s, while the impingement angles were 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees and 90 degrees. Silicon dioxide particles with average diameters of 250, 500 and 1000m were used as abrasive particles. Experimental data were taken as reference and values of erosion rates were obtained as functions of impact velocity, impingement angle and the size of the abrasive particles. The results obtained exhibited typical ductile behaviour of glass fibre-reinforced composites, where the maximum erosion rate was recorded at an impingement angle of 30 degrees, and the erosion rates decreased as the impingement angle increased. Moreover, the erosion rates increased with the increase in impact velocity and particle size. Finally, the worn out surfaces of the test specimens were investigated on two different devices, optical microscope and scanning electron microscope.