This study examines the socio-spatial transformations of Djelfa, Algeria in the contexts of its urbanization from 1990 to 2024, focusing on the transition from extended to nuclear family structures and from monocentric to polycentric urban forms. Utilizing a mixed-methods approach, including interviews, questionnaires, observations, and data analysis with 200 participants, the research outlines the adaptation of housing and urban space to meet the needs of Djelfa’s growing population. Key findings highlight a dramatic demographic shift marked by a 75.6% increase in population, a reduction in average household size from 6.3 to 4.1, and a 150% surge in the number of households. This demographic expansion has spurred extensive urban expansion, effectively doubling the built-up area and necessitating the development of sub-centres of the city to mitigate pressure on the primary city center (CC). This evolution underscores Djelfa’s progression towards a polycentric urban model, reflecting broader urban space decentralization and diversification trends to improve accessibility and reduce congestion. The study contributes to the understanding of complex effects that urbanization has on social and spatial structures in the Global South, highlighting the critical interplay between demographic shifts, urban planning, and social restructuring. Advocating for strategic, inclusive urban planning and policymaking, the research underscores the importance of addressing the diverse needs of rapidly urbanizing populations, offering invaluable insights into sustainable urban management practices applicable to similar urban scenarios worldwide.