Concrete is one of the most popular building materials used in the construction industry in the world. Cement is one of the primary materials used in concrete. Cement production results in enormous carbon dioxide emissions, leading to serious sustainability issues that badly affect the environment. As a solution, supplementary cementitious materials (SCMs) come into action. From various types of SCMs, agro-waste-based SCMs are becoming a promising solution. The potential of rice husk ash (RHA) as a supplementary cementitious material (SCM) to improve the environmental performance of concrete is examined in this study. RHA is a by-product of milling rice, and it can be used as a partial substitute for cement due to its pozzolanic qualities and high silica content. A Life Cycle Assessment (LCA) was carried out to evaluate the environmental effects of utilizing RHA in concrete, focusing on key indicators such as Global Warming Potential (GWP), energy consumption, and resource depletion. The results demonstrate that incorporating RHA significantly reduces the carbon footprint of concrete. Through the literature review, it can be seen that RHA can be used as an SCM in concrete production to improve its mechanical and durability properties, which is confirmed by the concrete experiment conducted during this study. This study highlights the importance of adopting agro-waste-based SCMs like RHA to promote sustainable construction practices and reduce the environmental burden of the construction industry.