This article analyses the complex relationship between impact assessments (IAs) of all types (such as comprehensive, regulatory, economic, social or environmental IAs) and their governance environment, using an analytical framework based on the concepts of governance styles and metagovernance. It is argued that each governance system builds on specific values, traditions and history and produces specific mixtures of hierarchical, network and market styles of governance (with or without an explicit metagovernance approach). Although governance can be considered as a non-normative perspective on polity and politics, the normative dimension of governance practice results in, for example, conflicting convictions about which type of knowledge or 'evidence' is valid for IA processes. This is particularly relevant because IAs have an important role in improving the knowledge base of governance. The concrete governance system in a specific country or other administrative entity influences the design and governance of IA systems positively or negatively, which leads to a variety of challenges. The conclusion is drawn that understanding the governance context and its dynamics can help improving IA governance.