<p>CO₂-assisted co-gasification has emerged as a promising thermochemical technology for sustainable energy production and waste management. This review explores the synergistic effects of combining various feedstocks, including biomass, coal, plastics, and mixed wastes, in CO2-assisted co-gasification processes. By utilizing CO₂ as a gasifying agent, this approach offers dual benefits: reducing greenhouse gas emissions and enhancing syngas yields with improved energy efficiency. The literature reviewed indicates that synergistic interactions between feedstocks can lead to notable improvements in key performance metrics such as syngas yields, carbon conversion rates, process reactivity, and hydrogen-to-carbon ratios, compared to the gasification of individual feedstocks. The addition of CO₂ optimizes gasification kinetics, allowing for a reduction in the formation of harmful tars and char. Advanced reactor designs, catalysts, and process optimization techniques have further improved performance, with some studies reporting calorific value enhancements of up to 10&#xa0;MJ/kg in selected cases, while minimizing environmental impacts. Despite these advantages, challenges remain in terms of feedstock variability, scalability, catalyst deactivation, and process energy requirements, which may limit near-term industrial adoption. This review provides comprehensive insights into the technological advancements and prospects of CO₂-assisted co-gasification, emphasizing its potential for biofuel production, chemical synthesis, and carbon-neutral energy systems. Future research focused on advanced catalysts and process integration will be crucial for bridging the gap from laboratory-scale success to industrial-scale application.</p>