The guilt that mothers feel about the time and energy that they invest in work instead of their family is often proposed to be an important reason for why mothers ‘opt-out’ the career track. We sought to understand if mothers indeed experience more workfamily guilt than fathers and how this relates to both their own gender role beliefs and organizational gender norms across nine European countries. Analyses draw on the European Social Workforce Survey, with data from 2619 working parents nested in 110 organizations in 9 European countries. Results showed that when fathers and mothers work more than a full-time week (a) fathers with traditional gender role beliefs felt less guilty, and (b) especially mothers working in an organization with low support for the parent role of working fathers felt guilty. Explorative analyses showed no effect of national gender norms on gender differences in guilt. Our results are beneficial for organizations and policy makers by showing that guilt in working mothers can be reduced by developing egalitarian organizational norms, in which there is support for the parent role of mothers and fathers, potentially helping mothers to focus on their careers alongside their families.