The addition of steel slag and reclaimed asphalt pavement (RAP) in the road pavements presents a compelling solution to the significant challenge of industrial waste management. The aim of current work is to examine how the addition of steel slag and RAP collected from industrial waste management plants impacts the mechanical characteristics of asphalt mixes with a particular emphasis on identifying the optimal mix proportions. In this research, various compositions of steel slag and RAP are utilized along with Viscosity Grade 30 (VG-30) bitumen for modifying the asphalt mixes. This study assess and compare the influence of these steel slag and RAP on the mechanical behavior of asphalt mixtures across varying concentrations aiming to enhance the overall performance and sustainability of flexible pavements. To prepare the asphalt mixtures, the properties of steel slag and RAP are studied. Laboratory experiments are conducted including penetration tests, softening point tests, ductility tests, and Marshall tests to analyze how steel slag and RAP affect factors such as stability, strength, durability, adhesion, economy, and environmental sustainability. The research outcomes demonstrate notable enhancements in asphalt mix properties following modification with steel slag and RAP, including reduced burden on natural aggregate, increased strength and improved overall lifespan, observed value with steel slag at 10, 20, and 30% composition of coarse aggregate and with RAP being constant at 30% composition of coarse aggregate. The compelling attributes of waste steel slag and RAP underscore its significance in new road construction.