This paper presents the manufacturing and the mechanical and thermomechanical properties of a bio-based glass fibre-reinforced polymer (GFRP) composite, produced by vacuum infusion, using an in-house high-performance bio-based unsaturated polyester resin (UPR) with more than 50 wt% of its content derived from renewable raw materials. Specimens were successfully produced, and their mechanical and thermomechanical properties was compared to an equivalent GFRP composite produced with conventional petroleum-based UPR and the same fibre architecture. The bio-based GFRP composite presented 538 MPa, 210 MPa, and 52 MPa of tensile, compressive, and shear strengths; 20 GPa, 24 GPa, and 2.5 GPa of tensile, compressive, and shear moduli; and 3.0%, 0.8%, and 14.8% of tensile, compressive, and shear strain at failure, meeting or exceeding the mechanical properties of the conventional counterpart. Furthermore, the bio-based GFRP composite presented a T-g of 64 degrees C (defined from onset of the storage modulus decay), enabling its outdoors use.