Previous literature on openness has mainly dealt with the consequences of openness. In this paper, however, we are interested in the cultural determinants of openness. Conducting a cross-country analysis incorporating 53 countries over the period 1959–1997, we find that several aspects of national culture have an impact on openness. Specifically, we find positive effects of individualism and negative effects of uncertainty avoidance and power distance on openness. These findings point to the importance of taking cultural influences into account in future research on openness. Interestingly, the cultural effects were found to become stronger over time and to smoothen out in the end of the study period. This result is in line with the idea that the effect of culture may be expressed most clearly in situations where freedom of choice for policy makers is greatest. When this freedom is restricted, because of scarcity reasons or because there is a dominant view on best practice, the possibility of cultural preferences to influence policy decisions seems to be smaller.