The study analyzes constructions of femininity and feminine sexuality in interpretations of the goddess Babalon, a central deity in the British occultist Aleister Crowley’s (1875–1947) religion Thelema. Babalon is based on Crowley’s positive reinterpretation of the biblical Whore of Babylon and symbolizes liberated female sexuality and the spiritual modality of passionate union with existence. Analyzing historical and contemporary written sources, qualitative interviews, and ethnographic fieldwork in the Anglo-American esoteric milieu, the study traces interpretations of Babalon from the works of Crowley and some of his key disciples—including the rocket scientist John Whiteside “Jack” Parsons and the enigmatic British occultist Kenneth Grant—from the fin-de-siècle to the present. From the 1990s onward, female and LGBTQ esotericists have challenged historical interpretations of Babalon, drawing on feminist and queer thought and conceptualizing femininity in new ways. Femininity has held a problematic position in feminist theory, often being associated with lack, artifice, and restriction. However, the present study—which assumes that femininities are neither exclusively heterosexual nor limited to women—indicates how interpretations of Babalon have both built on and challenged dominant gender logics. As the first academic monograph to analyze Crowley’s and his followers’ ideas from the perspective of gender, this book contributes to the underexplored study of gender in Western esotericism. By analyzing the development of a misogynistic biblical symbol into an image of feminine sexual freedom, the study also sheds light on interactions between Western esotericism and broader cultural and sociopolitical trends.