This book explores how monsters articulate questions about the sacred in nineteenth-century Irish Gothic literature. The relationship between religion and Gothic literature has traditionally been approached through denominational readings, but this study proposes how Irish Gothic texts from Charles Maturin's Melmoth the Wanderer to Le Fanu's 'Carmilla' and Bram Stoker's Dracula resist being inscribed into particular doctrinal frameworks. Abandoning allegorical interpretations, Theological Monsters proposes that real-life theologies do not translate into the fictional ones articulated across these texts. The focus is on revealing how the bodies of monsters make real and tangible otherwise abstract concepts associated with God and the afterlife, and on identifying monstrosity as a valuable way to uncover knowledge of the divine in nineteenth-century Irish Gothic literature. What follows is an original reassessment of three canonical writers - Maturin, Le Fanu and Stoker - highlighting their fictional theological exercises.