Urbanization in Guinea-Bissau has accelerated in recent decades, leading to a significant increase in informal settlements. This trend is accompanied by challenges in social welfare provision due to resource constraints and inadequate planning. A mixed-methods approach was employed, involving a structured questionnaire survey of households within selected urban areas. Secondary data from official records were also analysed to complement the findings. The survey revealed that approximately 45% of urban residents in Guinea-Bissau live in informal settlements without access to basic sanitation and healthcare facilities. Urbanization has brought both benefits and challenges, particularly affecting vulnerable populations. The need for targeted social welfare interventions is highlighted, especially in addressing the needs of informal settlement dwellers. Policy makers should prioritise the development of comprehensive urban planning strategies to accommodate future growth while ensuring equitable access to essential services.