Introduction: Access to clean and safe drinking water is essential for human health. However, in many regions, including Southwest Nigeria, drinking water contamination remains a critical issue. Lead (Pb) contamination, in particular, poses significant health risks, such as neurological damage and developmental issues in children. This research is novel as it provides a comprehensive assessment of lead levels in drinking water across a diverse region with varied socio-economic activities and environmental conditions. The primary aim of this study is to assess lead (Pb) contamination levels in drinking water samples from Ondo, Osun, and Ekiti States in Southwest Nigeria and the contamination factor (CF), enrichment factor (EF), and index of potential ecological risk (Eif). Methods: Water samples were collected from various sources, including wells, boreholes, rivers and streams, in the locations. The samples were analyzed for lead content using Atomic Absorption Spectroscopy (AAS). Results: The lead levels (0.003-0.077 mg/L) were then compared with National Environmental Standards and Regulations Enforcement Agency (NESREA) and World Health Organization (WHO) safety standards. The results indicated that a significant proportion of the water samples contained lead levels exceeding both NESREA and WHO safety standards. The results also depicted: All samples but one exhibited low Degree of Contamination and Contamination Factor, low EF and Eif. The highest contamination level was found in sample from a stream, likely due to proximity to a car wash shop, nearness to a moderately busy road, and the use of lead-containing materials in water distribution systems within the environ. Conclusion: The study concludes that lead contamination in drinking water is a pervasive issue in Southwest Nigeria, posing serious public health risks. The findings underscore the need for regular water quality monitoring, public awareness campaigns, and the implementation of stricter regulations to ensure safe drinking water.