As natural fibres, cotton fabrics (CF) offer good opportunities as reinforcement material for geopolymer composites as they have good intrinsic mechanical properties. This article presents thermal and mechanical properties of CF-reinforced geopolymer composites containing up to 4.1 wt% CF. Thermo-gravimetric analysis was conducted to characterise their thermal performance and their mechanical properties, such as flexural strength, fracture toughness, flexural modulus and impact strength were evaluated. Results show that the enhancement of mechanical properties was achieved at an optimum fibre content of 2.1 wt%. Results of thermal analysis show that fly-ash based geopolymer can prevent the degradation of cotton fabric at elevated temperatures.