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Longitudinal epidemiological studies in various countries have evaluated the relationship between neurodevelopment in childhood and exposure to pollutants currently or previously ubiquitous in the environment, such as lead, polychlorinated biphenyls (PCBs), dioxins, and air pollution. These mother–child or child cohort studies describe associations between exposure during the prenatal period or the first year of life and disruptions of mental and psychomotor development in young children, and cognitive deficits or behavioral problems in older children. It is also suggested that the impact of these exposures affects the risk of neurodevelopmental disorders (NDDs), such as attention deficit/hyperactivity disorder (ADHD), or autism spectrum disorders (ASDs). Specifically, prenatal exposure to lead is thought to affect the risk of ADHD, and particulate matter (PM) is suspected of affecting the risk of ASDs. Experimental studies show that these pollutants have various modes of action and mechanisms at the molecular and cellular level including oxidative stress, neuroendocrine and neurotransmission disturbances, and neuroinflammation, as well as epigenetic modifications that can impair brain development during the embryonic and fetal periods, and the acquisition of cognitive and behavioral skills during childhood.