This chapter aims to present a scoping review of the association between exposure to fluoride and low intelligence quotient (IQ) scores in children. The mechanism of fluoride in reducing IQ is still a matter of debate. Rats affected by chronic fluorosis may have altered membrane lipids that could be a cause of a brain disorder. It is suggested that in humans, high fluoride in the water can affect children’s cognitive abilities and mental development. However, concentrations of fluoride in the drinking water to provoke chronic fluorosis in rats need to be 5 times higher when compared to similar doses for humans. Scientific evidence for the fluoride-low IQ relationship comes mostly from case-control studies with low levels of evidence and problems related to confidence in exposure to the risk factor and potential risk of bias. In addition to water fluoride, some studies try to relate this problem to other fluoride methods, such as salt fluoridation and the regular use of fluoride toothpaste. It can be concluded that there is a lack of consistent prospective studies on this topic to conclusively assess the association between exposure to fluoride and low IQ scores in children.