The health effects of arsenic (As) exposure are a major global environmental issue affecting millions of people around the globe. Although adult epidemiological studies on As-induced health consequences have been extensively reviewed, but not much comprehensive review has been done targeting children. In this epidemiological review, 64 human subject studies on children were identified after applying exclusion criteria, which addressed an array of health effects of As exposure in early life stages in South and Southeast (S–SE) Asian countries, where a great variability in As exposures has been reported. The present review identified neurocognitive impairment linked to As exposure in early life stages. In utero and childhood As exposures were also associated with genetic and metabolic alteration, elevated pneumonia risk, and skin lesions in several populations in S–SE Asia. Significant associations of As with epigenetic changes, DNA damages, abnormal birth outcomes, and elevated mortality were also reported in epidemiological studies. The findings of this review article may help public health policymakers and clinicians develop early-life intervention strategies to reduce the burden of diseases in As-exposed populations.