Cellulosic ethanolCellulosic ethanol is produced from non-food lignocellulosic biomassLignocellulosic biomass and is a sustainable alternative to fossil fuels and first-generation biofuelsBiofuel. Despite its potential to reduce greenhouse gas emissionsEmissions and utilize abundant agricultural and forestry wasteWastes, commercializationCommercialization is currently hindered by financial and technological barriers. This chapter examines the pretreatmentPretreatments, enzymatic hydrolysisEnzymatic hydrolysis, and fermentation processes involved in producing cellulosic ethanol while addressing significant challenges such as refractory biomass structure, high enzyme prices, and inhibitor formation during conversion. Alongside significant technological limitationsLimitations like low conversion efficiency, scaling issues, and energy-intensive processes, economic barriers like high capital costs, feedstock logistics, and competitiveness with fossil fuels are also explored. Suggested approaches to successful commercializationCommercialization that emphasize advancements in enzyme engineering, metabolic engineeringMetabolic engineering of fermentative bacteria, integrated biorefineryBiorefinery models, and legislative incentives. Case studies of advanced technologies (e.g., CRISPR-edited yeast strains and centralized bioprocessing) and pilot-scale facilities demonstrate pathways to cost parity and scalability. This chapter provides a roadmap for reducing barriers to the widespread use of cellulosic ethanolCellulosic ethanol and ultimately aiding the transition to a circular bioeconomy by integrating interdisciplinary techniques, such as supply chain optimization and technological developments.