Though polymer composites are high-strength promising material, their wear damage is a real matter of concern in practical applications. Thus, to improve their wear performance, the polymers and composites are now increasingly being subjected to cryogenic treatment. Thus, an attempt has been made to cryogenically treat fiber and particulate-reinforced PBT composites and evaluate their structural and mechanical properties. In addition to this, as the interface between the filler and matrix material has a decisive effect on composite properties, the interface was also investigated and the change at the interface was monitored and evaluated through theoretical predictions as well. This work concludes that cryogenic treatment is rather effective for improving the mechanical properties of polymer composites, without compromising its structural integrity. The wear performance of the glass fiber-reinforced and wollastonite-reinforced PBT composites enhances by almost 84% and 96%, respectively, when treated at − 185 °C for 8 h.