This thesis delves into exploring lignin's potential as a sustainable substitute for bitumen within asphalt mixtures, with the overarching goal of reducing the environmental footprint of the asphalt industry. By conducting a meticulous blend of literature reviews and comprehensive laboratory experiments, the research examines the performance and ecological sustainability of lignin-infused asphalt mixtures. The primary objective is to assess lignin's efficacy as a binding agent in asphalt pavements and its potential to create more sustainable and environmentally friendly road materials. Key inquiries encompass comparative analyses of lignin-based asphalt mixtures against conventional bitumen-based counterparts, alongside an exploration of the environmental advantages and challenges associated with lignin utilization. Through laboratory assessments and analyses, including examinations of tensile strength, permanent deformation and air voids, the study evaluates the performance and sustainability of lignin-infused mixtures. Notable findings indicate significant environmental benefits, such as reduced CO2 emissions and enhanced water resistance. However, despite promising results meeting Swedish Transport Administration requirements, further optimization is essential to enhance competitiveness.