While the number of think tanks in Denmark has increased considerably in recent decades, our knowledge about their visibility in political arenas is limited. The article explores how and why the mentions of private and public think tanks in the parliamentary and media arenas has developed from 2005 to 2018. Building on insights from previous studies of think tanks, publicly funded think tanks are expected to achieve more parliamentary mentions than private think tanks because they are expected to be more heavily influenced by institutionalized norms to target inside actors through parliament. By contrast, privately funded think tanks are expected to achieve more media mentions than public think tanks, because they are policymaking outsiders and emphasize public advocacy over direct influence. Although publicly funded think tanks have been more visible in the parliamentary arena than private think tanks, their visibility has declined. Private think tanks are more visible than public think tanks, but media visibility for privately funded think tanks also drops towards the end of the period. The article concludes that public or private funding cannot fully explain changes in think tank visibility in the two arenas over time. Instead media and parliamentary mentions are driven by a handful of think tanks while most think tanks struggle to achieve and maintain parliamentary and media visibility over time.