Male parental investment can contribute to the fitness of both sexes through increased fertility and child survivorship. The level and intensity of parental investment are dependent upon ecological variations: in harsh and demanding environments, the need for biparental care increases. Moreover, when environmental pressures increase, uncertainty over paternity may lead to favoring stricter mate-guarding practices, thus directing males to invest more effort toward controlling and guarding their mates from infidelity. In this paper, we test the hypothesis that religious veiling, as a social and cultural practice which regulates and restricts sexuality, will be more important in harsher environments. Our results show that harsh and demanding environments are associated with the importance of religious veiling and the level of religiosity, providing a link between cultural practices such as religious veiling and ecological variation.