Gentrification refers to a transformation in the composition of land users whereby in-coming users possess a higher socio-economic status than those they replace, accompanied by reinvestment in the built environment and the physical transformation of urban space. Displacement is an essential part of this process. Gentrification has become one of the central analytical concepts in urban studies. Gentrification has become one of the central analytical concepts in urban studies enabling the analysis of socio-spatial restructuring processes in cities and has been applied to a broad range of geographical settings and historical conditions. Originally coined in the context of post-war London, the concept has since traveled widely and has been applied to a broad range of geographical settings and historical conditions. This entry provides a comprehensive overview of the evolution of the concept, its principal theoretical interpretations, and its empirical applications. It reviews the major strands of explanation—demand-side, supply-side, and institutionalist approaches—and situates them within broader debates in urban theory. Particular attention is devoted to the relationship between gentrification and displacement, including both classical conceptualizations and recent efforts to capture its more diffuse and subjective dimensions. The entry concludes by arguing that while gentrification remains a key concept for analyzing urban change, it must be continuously reworked in light of emerging dynamics such as financialization, digitalization, and trans-local housing practices. It calls for more systematic and genuinely comparative research in order to better understand the evolving geographies of gentrification.