The European Union is a world leader in nanotechnology environmental, health and safety (EHS) risk regulation, and since its policy integration has been increasingly active in promoting international coordination and cooperation on nanotechnology risk governance. What affects its ability to influence nanotechnology risk regulation and governance internationally? This analysis focuses on the European Union (EU) level arguing that the EU’s scientific and regulatory capacities have significant explanatory power. Empirically, the article examines three cases of EU influence in key areas of international nanotechnology risk regulation and governance – nanosafety research for regulatory purpose, science diplomacy, and multilateral risk governance, following its integrated policy.