Turkey's role in the Iranian nuclear dossier is often portrayed as that of a 'facilitator' and 'mediator' in scholarly analyses. NATO member Turkey was seen as a potential bridge-builder between the Islamic Republic of Iran and the 'Western camp' of negotiators. During prime minister Erdoğan's first legislature, however, Ankara's and Washington's foreign policy outlooks and strategic priorities started to diverge in the course of Turkey's new regional engagement in what has been theorized as a 'Middle-Easternization' of Turkish foreign policy. It is Turkey's location as a geostrategic hub in a politically instable region that informed Turkey's 'Zero problems with neighbors' policy and foreign minister Davutoğlu's advocacy for a 'Strategic Depth' in Turkey's foreign and regional policies. Ankara emphasizes its need to uphold sound relations with its neighbors and publicly stresses an unwillingness to go along with Western pressure on Iran, and insists on the principle of non-interference and Iran's right to use nuclear power for peaceful purposes. All the same, Turkish-Iranian relations are undergoing a deterioration in the wake of the Syrian civil war at the time of writing, with both sides supporting diametrically opposite causes and factions. Turkish-Iranian fundamentally differing conceptions of regional order will also impact upon Turkey's leverage power to defuse the Iranian nuclear crisis. This paper therefore adds a timely contribution to our understanding of a multifaceted and nuanced Turkish foreign policy toward Iran that can be a critical complement to 'Western' diplomatic initiatives in the search for new paradigms for a new Middle East order.