This chapter examines the urban development of Alexandria in Late Antiquity, tracing its transformation from a Hellenistic metropolis into a vital centre of Roman and Byzantine administration, commerce and religion. It analyses architectural and archaeological evidence to explore how the city’s infrastructure evolved in response to political shifts and economic changes. Particular attention is given to Alexandria’s grid-plan layout, monumental public buildings and role as a Mediterranean trade hub. The chapter outlines key construction phases, including Ptolemaic urban planning, Roman imperial projects and late antique renovations. Excavations at Kom el-Dikka provide crucial insights into the city’s residential, commercial and academic landscapes, revealing lecture halls, baths and artisanal workshops. This study also examines the impact of religious transformation, documenting the conversion of pagan temples into Christian churches and the rise of new ecclesiastical structures. Further emphasising Alexandria’s role as a major intellectual centre, the study highlights its famous auditoria and the persistence of scholarly activity even after the decline of its classical library tradition. Despite the challenges posed by modern urban expansion, ongoing excavations continue to refine our understanding of Alexandria’s resilience and adaptability in Late Antiquity.