This paper develops a theoretical foundation to describe and explain impediments to organizational learning (OL). Based on the expanded 4I model (Crossan et al. 1999. Academy of Management Review, 24, 522–537), which was further developed by Lawrence et al. (2005. Academy of Management Review, 30, 180–191), different learning barriers are categorized and discussed with regard to factors complicating or impeding OL. Finally, the paper analyses the impact of particular barriers on different kinds of organizational units, the relationship between OL barriers, single-loop and double-loop learning, as well as typical combinations of barriers and their respective impact on organizational performance.