This dissertation critically investigates the transnational movements that shaped the making of modernist poetry in Iraq and Iran. Following a brief introduction to the project’s historical and critical framework, the first chapter provides the dissertation’s theoretical foundation. It thus engages conversations about literary commitment, the transnational dimension of literary development, and world literature to situate these two poetries as integral to the broader modernist movement. Chapter Two examines the poetry of Nīmā Yūshīj, the founder of Persian modernist poetry, and the foundational position of premodern Arabic prosody for Persian poetic form. It highlights how Nīmā’s innovations on Arabic prosody presage the birth of the Iraqi free verse movement. Chapter Three moves on to discuss the work of Iraqi poet Badr Shākir al-Sayyāb, addressing how his pioneering project of poetic modernism changed in light of his political alignments. It demonstrates how his experience of the 1953 coup against Mosaddegh in Iran forced him to reconsider his Communist affiliations and discerns the effects his changing political outlook had on how he presented his poetry for posterity. Aḥmad Shāmlū and Furūgh Farrukhzād, two poets who took up Nīmā’s modernist vision in Iran, are the subjects of Chapter Four, which tackles their continued development of Arabic prosody in Persian and ultimate break with the formal constraints Nīmā had continued to adhere to. It also considers Shāmlū’s and Farrukhzād’s contrasting poetics of death in terms of their transnational poetic engagements. The final chapter turns to examine the Iraqi poet ʿAbd al-Wahhāb al-Bayātī’s poetics of revolution—which combines existentialism, Sufism, and political commitment—to show how al-Bayātī’s use of the poetic masks of ʿUmar al-Khayyām and the martyred Sufi Manṣūr al-Ḥallāj works in transnational dialog with the Persian poetic and mystical traditions. By taking the Arabic modernist tradition as its focal point and putting Arabic poetry in conversation with modernist poetry in Persian, this study sheds light on how modernism functions as a planetary movement and calls for a reconsideration of current models for transnational literary analysis, reorienting modernist studies away from vertical approaches to lateral ones that consider minor modernist traditions on their own terms.