This paper attempts to assess and explain the relative strength of internal and external factors in the improvement of Turkey's human rights regime. After 1999, the European Union, which required Turkey to conform to the 'Copenhagen criteria' of civil liberties as a precondition for the start of accession negotiations, has been by far the most important element, resulting in the passage of an impressive raft of constitutional and legal reforms between 2001 and 2004. After 2005, when accession talks officially began, the pace of reform slackened markedly, as the accession process became more problematic. Nonetheless, in 2010, another package of constitutional reforms was enacted, suggesting that the cause of reform has now acquired a powerful internal dynamic.