One of the unsolved puzzles in democratization studies today is the prevalence of authoritarian regimes in the Middle East. Previous comparative studies have overlooked the region because it does not contain a single case of successful democratization. Middle Eastern scholars, on the other hand, tend to lack the theoretical tools on what it would take for this area to democratize. The purpose of this study is to elucidate the factors behind the level of (non-)democratization in the MENA-region. I will argue that democratization in the Middle East takes place on three different levels: international, national and societal. The study combines statistical data with process tracing analysis, in order to corroborate the evidence. Twelve variables, covering a wide range of democratization theories, are tested on four cases: Egypt, Iran, Saudi Arabia and Turkey. From this, I am able to confirm or discard certain theories, as well as establish the factors that are relevant for each case. Among other things, I am able to refute the claim that a Muslim population affects democratization negatively; to confirm the validity of the rentier state theory; to show that path dependency and political parties matter; and that FDI and aid can play a part in the future democratization of the Middle East.