ABSTRACT This study explored the effect of fibre orientation on the mechanical properties of Betel Nut (Areca palm) stem fibres (BNSF)-reinforced laminated polyester composites. Composites are fabricated by hand lay-up method with 15% (vol.) fibre loading and 0°/90°/0° and −45°/0°/45° orientations. The mechanical properties of composites are determined by testing as per ASTM standards and revealed that composite strengths vary significantly with fibre orientation. The tensile, flexural, and impact strengths of the composite are found 58.19 MPa, 153.96 MPa, and 25.68 kJ/m2, respectively, for the 0°/90°/0° fibre orientation, which are higher than the composite of −45°/0°/45° fibre orientation. Furthermore, strengths are found greater than the betel nut husk and leaf, bamboo, coir, banana, and jute fibres-reinforced polymer composites. The bonding between fibres and matrix, voids, micro-cracks, etc. are investigated by optical microscopy of a tensile-fractured specimen. This study revealed that BNSF would be a novel and potential natural fibre for reinforcing polymer composites. Its strength can be enhanced by choosing suitable numbers of fibre laminations and orientations. Since areca palm trees grow extended, moderate-sized composite boards/panels can be produced from BNSF to replace synthetic fibres-based ones. It will help reduce environmental pollution as a green composite.