This article examines the discreet but multiple references to the Trojan princess Cassandra in Sartre’s work, from his earliest writings to the more political texts of the 1960s and his final play, The Trojan Women. The unfortunate prophetess, condemned to speak the truth and never to be believed, is featured in Sartre’s writings in a number of ways. In the early texts of the 1920s, Cassandra is linked to the pursuit of the truth, romantic and post-romantic literature and the metaphor of the veil. The following decade, she is mentioned again in Nausea in connection with Sartre’s phenomenological concerns. Finally, in the polemical prefaces of the 1960s and The Trojan Women, she serves to highlight problems associated with the unwelcome political truths of the committed writer. Tracing the evolution of this multifaceted figure in Sartre’s thought allows us to better evaluate Sartre’s secret passion for Cassandra.