The effect of adding rubber on the properties of glass-fibre-filled nylon 66 was investigated in this study. Styrene-Ethylene-Butylene-Styrene and Ethylene-Propylene elastomers grafted with maleic anhydride (SEBS-g-MA and EP-g-MA, respectively) were used to toughen the nylon-matrix composites. Impact strength and elongation at break were found to increase with increasing rubber content, but flexural strength, tensile strength and stiffness decreased; however, by adding moderate amounts of rubber to glass-fibre-reinforced nylon 66, a desirable balance between stiffness and toughness of the material may be obtained. For example, the addition of 10 wt.% of SEBS-g-MA to nylon 66 with 23.62 wt.% glass fibre loading resulted in 28.3% and 167% increase in tensile strength and impact strength of the composites, respectively, when compared to neat nylon 66. This suggests that combining both glass fibres and rubber with nylon 66 is a useful strategy to optimize and enhance the properties of nylon 66. The procedure may be used to recycle polyamides, in general, and to develop components for under-the-hood automotive applications, in particular.