This study is aimed at investigating short- and long-term aged properties of glass fibre (GF)-reinforced asphalt mixtures using indirect tensile strength (ITS) and associated fracture energy, moisture susceptibility, creep compliance, resilient modulus, and indirect tension continuous and discontinuous (IDT) fatigue tests. Also, to portray the influence of fibre reinforcement at micro level, a micromechanical finite element model (MFEM) was built utilising representative volume element (RVE) to consider the effect of fibre dose, length, and dispersion (fully aligned or random) on the mechanical characteristics (or stress-strain curve) of the composite under unidirectional strain perturbation. Based on the study results, for the same binder, compared to shorter fibre (i.e. 6-mm length), the application of 12-mm GF to the mixtures showed unnoticeable change in the short- and long-term properties of the reinforced mixtures. On the whole, the GF can impart positive characteristics to the asphalt mixture such as increase strength, resistance to rutting, less susceptibility to moisture damage, retard fatigue cracking, enhance healing capability, and combat adverse aging changes. Unlike the effect of fibre length, the numerical model proved that the orientation and concentration of GF showed noticeable influence on the mechanical response of the composite. Overall, using the GF in asphalt mixtures can help produce durable bituminous pavements. Although the present study investigated the GFreinforced bituminous materials from performance stand point, one can speculate that building GFreinforced pavements is more costly initially compared to unreinforced pavements however the benefits may be received over time by extending service life and saving the maintenance cost of the bituminous pavement