This paper examines the development of Lightweight geopolymer concrete through a polymerization process triggered by the combination of fly ash and GGBFS with lightweight aggregates and alkali activators. It delves into the impact of GGBFS on the mechanical, durability, and microstructural properties of LWGPC under varying curing conditions, including temperature and ambient settings. Through a detailed analysis, this study assesses the flexural tensile strength, splitting tensile strength, and compressive strength of LWGPC specimens. Ambient curing fosters the pozzolanic reaction of GGBFS, accelerating the chemical processes of LWGPC. Furthermore, this research investigates the durability and microstructural attributes of LWGPC to elucidate the pozzolanic behavior of GGBFS. Emphasizing the utilization of GGBFS as an industrial by-product, the paper underscores its role in promoting the sustainable development of lightweight geopolymers.