This article examines the heritage destruction undertaken by the Islamic State (IS) in Iraq and Syria. To date, their iconoclasm has been mostly characterised either as acts of wanton barbarism devoid of religious or political justification, or as a cynical performance designed as a mass media spectacle. Drawing on a systematic analysis of two key IS propaganda outlets – their on-line magazine, Dabiq, and the various slick films released by Al-Hayat – this article argues that the heritage destruction perpetrated by the IS are not only situated within a carefully articulated theological framework and key to the creation of a new and ideologically pure ‘Islamic State’, but that they are also constituted by several complex layers of religious and political iconoclasm. To demonstrate, this article documents the iconoclasm undertaken by the IS along two key axes: Symbolic Sectarianism (Shia and Sufi mosques and shrines); and Pre-Monotheistic Iconoclasm (ancient polytheistic sites). Attacks on key sites within these categories, such as the Sayyida Zaynab shrine in Damascus or the Mosul Museum, not only adhere to their religious and political framework but also serve broader geo-political agendas and are attacked as proxy targets for their physical and ideological opponents.