Prostate-specific membrane antigen (PSMA) has been the subject of extensive investigation in the past two decades as a promising molecular target for prostate cancer (PCa). Its appealing molecular features have enabled the development of a novel diagnostic and therapeutic—thus “theranostic”—approach to PCa. There is now substantial evidence of the high sensitivity of PSMA-targeted imaging for PCa lesions and growing evidence of the therapeutic efficacy of PSMA radioligand therapy for metastatic castration-resistant prostate cancer. This article presents a broad overview of the current status of PSMA theranostics, including current evidence, potential clinical impact, and active areas of research.