Shelter remains a fundamental human necessity, yet rapid urbanization, population growth, environmental degradation, and socio-economic inequalities continue to intensify housing and settlement-related challenges worldwide. This systematic review examines shelter issues through the principles of Ekistics, the interdisciplinary theory developed to understand and organize human settlements in relation to nature, society, infrastructure, and human needs. The study synthesizes scholarly literature, policy reports, and urban planning frameworks to identify the major causes of inadequate shelter, including overcrowding, informal settlements, poor infrastructure, lack of affordability, environmental vulnerability, and ineffective governance. By applying the principles of Ekistics, the review explores how balanced relationships among human beings, society, nature, networks, and built structures can contribute to sustainable and inclusive shelter development. The findings reveal that integrated planning approaches rooted in Ekistics can significantly improve housing quality, accessibility, environmental sustainability, and social well-being. Furthermore, the review highlights the importance of participatory planning, resilient infrastructure, equitable land distribution, and context-sensitive architectural practices in resolving shelter-related problems. The study also emphasizes the relevance of Ekistics in achieving sustainable urban development goals, particularly in developing nations facing rapid urban expansion. Through a comprehensive analysis of existing research, this review provides a conceptual framework for policymakers, urban planners, architects, and researchers to address contemporary shelter challenges systematically. The paper concludes that adopting Ekistics-based planning principles can foster resilient, liveable, and sustainable human settlements capable of meeting present and future housing demands effectively