This article explores how Islamic art was produced and used in Turkey within the context of modern warfare during World War I, the War of Independence, and the nascent Republic – a subject still relatively understudied in Turkish history, as well as in international cultural histories of modern warfare and histories of modern art in the Middle East. Drawing on previously overlooked visual and textual sources such as calligraphic panels, miniature paintings, war posters, and religious timetables produced during the years 1914–1924, we examine the ways in which Islamic arts were articulated with the experience of war through both individual actions and official policies, revealing how Ottoman artists tried to make sense of war and how Islamic genres and motifs were appropriated, and sometimes subverted, in the service of the nationalist cause. We show that far from exhibiting a sharp discontinuity, the transition from Ottoman–Islamic to Republican–nationalist artistic content was gradual, involving the reappropriation and repurposing of Islamic motifs and techniques in a manner that reflected the religious mindset of the elites and masses in the early twentieth century.