This study investigates the influence of compatibilizer type on the mechanical performance of 30 wt% glass fiber-reinforced polyketone (PK) and PK/Polyamide 6 (PA6) composites. Two compatibilizers, ethylene terpolymer (C1) and maleic anhydride grafted polyethylene (C2), were employed to improve interfacial adhesion and phase dispersion. Results show that the use of C2 significantly enhances impact resistance and elongation at break without severely compromising stiffness. Compared to unmodified composites, C2-modified samples demonstrated up to 113% improvement in impact strength and over 160% increase in strain at break. These findings highlight the critical role of compatibilizer chemistry in enhancing ductility and toughness in glass fiber-reinforced hybrid systems. In comparison with preceding studies, the present work introduces a systematic evaluation of compatibilizer chemistry in glass fibre-reinforced PK/PA6 hybrids. This evaluation reveals that the maleic anhydride group plays a dominant role in energy absorption. These findings demonstrate that selecting an appropriate compatibiliser is crucial for developing high-toughness and recyclable PK-based composites for engineering applications.