Expansive soils pose significant challenges in geotechnical engineering due to their high swell shrink behavior. Stabilization techniques are commonly employed to improve the engineering properties of such soils. This study investigates the potential of steel slag, a byproduct of the steel-making process with inherent CO2 sequestration capacities, as a stabilizing agent for expansive clays (EC). The research aims to evaluate the effects of steel slag addition on the Unconfined Compressive Strength (UCS) of stabilized soil samples. Laboratory experiments were conducted using varying proportions of steel slag mixed with EC. The UCS tests were performed at different curing periods to assess the time-dependent effects of the stabilization process. Results indicate that the incorporation of steel slag into EC yields notable improvements in the UCS values. The steel slag acts as a reinforcing agent, enhancing the mechanical properties of the soil. Additionally, the CO2 sequestration capacities of the steel slag contribute to the sustainable aspect of the soil stabilization process by offsetting greenhouse gas emissions. The outcomes revealed that the carbon sequestration capacity of the stabilized soil increased with an increase in the steel slag content. Overall, this research highlights the potential of steel slag as an effective and sustainable stabilizing agent for EC. The findings offer valuable insights for geotechnical engineers and researchers seeking environmentally friendly solutions to enhance the engineering properties of EC. By addressing the CO2 sequestration capacities of steel slag, this study contributes to the development of eco-friendly and cost-effective strategies for soil stabilization in infrastructure projects and land reclamation initiatives.