Risk governance has in recent years become a commonly used concept in relation to the understanding, assessment, management and communication of risk or risk problems, including so-called systemic risks. Substantial scientific work has been conducted to establish a proper foundation for this concept and its applications. Nonetheless, there are still some issues that remain to be clarified, for example how to best characterise risks and risk problems that need risk governance approaches. The purpose of the present article is to provide new insights into the risk governance concept by critically examining some common definitions and uses of key terms. In particular, the article seeks to shed new light on the interpretation of risk-problem classes: simple, complex, uncertain and ambiguous. A set of recommendations is presented on how to improve current risk governance theories and practices, including a suggestion for a modified risk-problem classification system.