This research constitutes an attempt to explain the slow progress in Turkey’s accession process over the years 2005-2013. In order to explore this situation, six hypotheses were formulated, based on studies on EU integration. These hypotheses include notions that according to literature constitute possible factors that explain the progress of a candidate country in complying with the EU conditions. In particular, these are: credibility of threats and promises; presence of intermediary rewards; domestic Euroscepticism; number of domestic veto players; institutional capacity; the inclination in the political regime. These factors were operationalized into particular indicators. In this context, it can be concluded that Turkey’s progress was slowed down to a great extent due to the examined factors, since four of them were fully confirmed (credibility of threats and promises; domestic Euroscepticism; number of domestic veto players; the inclination in the political regime) and two of them were partially confirmed (presence of intermediary rewards; institutional capacity).