This article examines patterns of oppositional behaviour in the GermanBundestag’s Committee on European Union Affairs (EAC) for two separate legislative periods (2005–2009 and 2009–2013). The study makes two contributionsto previous research. It, first, shed some much-needed empirical light on politicalopposition in the Bundestag by examining how much and what kind of opposition exists in the German EAC. Secondly, the article examines the differences inoppositional behaviour of the Members of Parliament between the two legislative periods following an institutional reform in 2009 that afforded theBundestag with increased opportunity structures in Europen Union affairs.