Urban expansion has become one of the most significant drivers of land-use change and environmental transformation worldwide, particularly in developing countries where rapid population growth and economic development have intensified pressure on limited land resources. While urbanization contributes to economic growth, infrastructure development, and improved access to social services, uncontrolled urban expansion often results in the conversion of agricultural land, deforestation, habitat fragmentation, biodiversity loss, soil degradation, and increased environmental pollution. This study examined the effects of urban expansion on land resources and environmental sustainability with a focus on identifying the major drivers of urban growth, assessing its impacts on land resources, evaluating its implications for environmental sustainability, and proposing sustainable urban planning strategies. The study adopted a qualitative desktop review research design based on the systematic analysis of peer-reviewed journal articles, books, government publications, and reports from international organizations, including the United Nations, the Food and Agriculture Organization (FAO), the United Nations Environment Programme (UNEP), the World Bank, and the Intergovernmental Panel on Climate Change (IPCC). Data were analyzed using thematic content analysis to identify recurring patterns and emerging issues across the reviewed literature. The findings revealed that rapid population growth, rural–urban migration, industrialization, infrastructure development, weak land-use planning, and ineffective environmental governance are the principal drivers of urban expansion. The review further showed that uncontrolled urban growth accelerates land degradation, loss of agricultural land, deforestation, biodiversity decline, increased flood risk, environmental pollution, and greenhouse gas emissions, thereby undermining environmental sustainability. The study concludes that sustainable urban development requires integrated land-use planning, stronger environmental governance, investment in green infrastructure, ecosystem restoration, and active stakeholder participation. It recommends the adoption of smart growth principles, enforcement of land-use regulations, and nature-based solutions to promote resilient cities and long-term environmental sustainability.