Lightweight concrete is gaining increasing significance in the construction industry due to its numerous advantages over conventional concrete. It can be produced by partially or fully replacing conventional coarse aggregates with lightweight aggregates. Laboratory tests were conducted to assess the feasibility of utilizing solid waste, such as cinders, for manufacturing lightweight aggregate concrete. The mechanical properties of cinder aggregate lightweight concrete were improved through the introduction micro-reinforcements. Polypropylene fibres were incorporated as micro-reinforcements at volume fractions of 0.1%, 0.2%, 0.3%, and 0.4%. The experimental results, including compressive strength, flexural strength, and modulus of elasticity, demonstrated that waste cinder aggregates can effectively replace coarse aggregates in lightweight concrete. Furthermore, the incorporation of polypropylene fibres enhances the mechanical performance of cinder aggregate lightweight concrete.