This dissertation examines the interrelationships between child labor, schooling and health, using nationally representative data from the United States and from Brazil. In developing countries, child labor can begin at an early age. However, child labor can be found in developed countries as well, particularly in the teenage years. This dissertation examines (1) whether and how much current state child labor legislation affects the employment and schooling decisions of U.S. high school students; (2) whether there is a cumulative effect of teen work on schooling outcomes; and (3) whether adults who worked as children experience increased incidence of illness or physical disability in Brazil. Variation in state government restrictions on child labor, the availability and quality of local schools, and the opportunity cost of schooling are used as instruments to correct for the potential endogeneity of child labor or years of schooling. This dissertation shows that U.S. child labor laws are not effectively enforced in limiting teen labor supply or in improving schooling outcomes. Nevertheless, child labor does have adverse consequences on lifetime learning and health, even if the work is legal and not of the "worst forms" of child labor, although these consequences are often of modest magnitudes. These findings suggest that policies limiting child labor may be justified as a means of improving the child's welfare later in life, but weak enforcement means that such policies have been only modestly successful in the past.