This paper aims to examine the role of national culture in the relationship between sustainability practices (social and environmental practices) and sustainability performance (social and environmental performance). While previous literature has focused on the influence of national culture on the decision-making and ethical behaviors of managers, the role of national culture on the effectiveness of sustainability practices has been rather neglected. Our study addresses this gap by highlighting the relevance of national culture as a contextual element when implementing sustainability practices in different countries. Based on a multi-level regression analysis using data from 484 firms in nine countries (China, Germany, Hungary, India, Italy, Japan, Malaysia, Slovenia, and Sweden), we found that the impact of social practices on social performance is accentuated in countries characterized by high uncertainty avoidance and high masculinity. The impact of environmental practices on environmental performance, however, is not affected by national culture.