This study involved a multiethnic cohort of 5711 six-year-old children living in a densely populated area of the Netherlands to examine whether differences in myopia prevalences in socioeconomic risk groups could be explained by differences in lifestyle factors. Findings indicated that children with myopia spent more time indoors and less time outdoors than children without myopia. The children with myopia also had lower vitamin D levels, a higher body mass index, and participated less in sports. Additionally, children of non-European descent, low maternal education, and low family income were more often myopic. They were also more likely to live with unmarried parents and to live in a rental home. Young children from families with a non-European ethnic background and/or a low socioeconomic status tended to be more often myopic in Rotterdam, one of the most densely-populated cities in The Netherlands. These findings suggest that the risk profiles based on education and income are not the cause of myopia, but reflect certain lifestyle factors that are more directly involved in the development of myopia.