This introductory article conceptualizes the notion of third country influence on European Union (EU) law and policy and proposes an analytical framework theorizing the venues and means through which third countries may gain such impact, under what conditions and with which implications for the EU's legal and political order. The article first introduces the focus on outside‐in influence in the context of European studies, generally, and EU privileged third country relations, specifically. Thereafter, an analytical framework is developed for mapping and explaining the outside‐in dynamics on EU law and policy‐making differentiating between diplomatic, governance and discursive venues; coercive versus technocratic and normative mechanisms of influence; and the legal constraints and political implications of these processes. Turning to the potential determinants of these occurrences, the article then proposes a set of hypotheses for conditions under which third countries can influence EU law and policies, before summarizing the individual contributions to this Special Issue.