The rise and subsequent erosion of friendly relations between Iran and Turkey was a result of their regional ambitions. While Turkey had long seen its secular system as presenting an alternative to Iran’s Islamic ideology, the alignment of their regional interests facilitated a rapport between the two states in the first decade of the twenty-first century. However, the Arab Spring proved divisive for this relationship as each state sought to advocate its model of government and secure a leadership role in the Arab world. The war in Syria widened the divide, as Iran’s long-standing support for the Bashar al-Assad regime could not be reconciled with Turkey’s desire to see President Assad out of office. Using a close reading of Persian and Turkish sources, the authors will analyse the Iran–Turkey divide, focusing specifically on how the Iranians have portrayed it as a clash of civilisations, citing Turkey’s so-called ‘neo-Ottoman’ ambitions as the primary cause.