Natural fibres may be a good alternative to synthetic fibres when reinforcing polymer composites in order to maintain a healthy environment. Cotton is a natural fibre with many benefits, including low density, good heat conductivity, high flexibility, resilience, elasticity and renewability. Cotton's crystalline and fibrillar structure accounts for its exceptional strength. We were inspired to conduct this review because of the potential of cotton fibre, as well as its mass production and low cost. This article reviews and summarises the mechanical properties of cotton fibre-reinforced polymer composites, including their flexural, tensile and impact properties. The effect of compatibilizers on the adhesion of two different phases of a composite material was also investigated in this study. Cotton fibre-reinforced composites were investigated as a replacement for desirable features by the textile, building and automotive industries. The industrial applications of cotton fibre-reinforced polymer composites are also highlighted in the final section.