This study examines determinants of materiality disclosure quality (MDQ) in integrated reporting (IR) in an international setting. To this purpose, we constructed a novel, hand-collected MDQ score in line with the <IR> guiding principles introduced by the International Integrated Reporting Council. On the basis of a cross-national sample consisting of 359 firm-year observations between 2013 and 2016, we find that MDQ is positively associated with learning effects, gender diversity, and the assurance of nonfinancial information in the integrated report. On the other hand, we find that IR readability, listing in the Dow Jones Sustainability Index, and earnings management do not affect MDQ. Our results are robust to different statistical models. We expand on earlier empirical findings on IR disclosure quality and provide valuable insights for research, practice, and standard setting.