<p>Waste gasification is a promising route for sustainable hydrogen production, yet its deployment remains highly uneven across regions. This review critically analyzes the technological, economic, environmental, and socio-political constraints governing waste gasification in industrialized and emerging economies, with particular emphasis on feedstock heterogeneity, cost competitiveness, and governance challenges. Key research gaps are identified, including the limited availability of experimental studies on unsegregated wastes, the underutilization of process intensification strategies such as high-gravity and membrane-assisted gasifiers, and the lack of integrated environmental and social life cycle assessments under real-world conditions. Based on these insights, a regionalized deployment roadmap is proposed, distinguishing large-scale gasification systems with integrated CO₂ capture in China, the United States, and Europe from decentralized, modular, and digitally assisted configurations tailored to Latin America and Africa. Sustainability benefits differ markedly by region, with emission reduction and circularity gains in industrialized economies and improvements in energy access, waste management, and social inclusion in emerging regions. Pilot-scale evidence further indicates that biomass–plastic co-gasification can enhance hydrogen yields by up to 90–110% under optimized conditions.</p>