A significant number of –mostly Western European– countries have recently newly introduced citizenship tests or have added stricter requirements of civic knowledge to previously existing language tests. This working paper collects the contributions to a EUDO-CITIZENSHIP forum debate on whether such tests can be defended from a liberal perspective. The question: ‘How liberal are citizenship tests?’ can be interpreted in two ways: as a question whether applicants for naturalisation should be tested at all, or as a question about specific modes, (...) contents and consequences of such tests that may make them either liberal or illiberal. In his kickoff contribution, Christian Joppke suggests an answer in line with the second interpretation by focusing on modes and contents. In his view, citizenship tests are defensible if applicants have reasonable opportunities to prepare for them and if questions are not inquisitive about individuals values and beliefs. Other authors claim instead that the most problematic feature of citizenship tests is the intention or effect of raising hurdles for naturalisation among long-term resident immigrants. Joseph Carens defends the view that ‘the most liberal citizenship test is none at all’. Ten authors have contributed to this lively and controversial debate, which concludes with a rejoinder by Christian Joppke. (shrink)