There is a vague relationship between corporate sustainability performance and reporting. In this contribution, this is discussed in terms of a ‘performance-reporting gap’. The gap is described and analyzed as problematic from an information use and relevance perspective and from an internal sustainability control perspective. An overarching consequence of the gap is that the quality and usability of information in sustainability reports depend on how companies treat the gap. In addition, the gap reflects underdeveloped processes of sustainability control in companies. It is suggested that the gap could be narrowed through clearer accountability structures and controllable sustainability processes within firms, more sophisticated materiality analyses and relevant strategic planning and pursuit of reporting processes.