Objectives: Testosterone (T) has an integral, albeit complex, relationship with social behavior, especially in the domains of aggression and competition. However, examining this relationship in humans is challenging given the often covert and subtle nature of human aggression and status-seeking. The present study aimed to investigate whether T levels and genetic polymorphisms in the AR gene are associated with social behavior assessed via natural language use. Methods: We used unobtrusive, behavioral, real-world ambulatory assessments of men in partnered heterosexual relationships to examine the relationship between plasma T levels, variation in the androgen receptor (AR) gene, and spontaneous, everyday language in three interpersonal contexts: with romantic partners, with co-workers, and with their children. Results: Men's T levels were positively correlated with their use of achievement words with their children, and the number of AR CAG trinucleotide repeats was inversely correlated with their use of anger and reward words with their children. T levels were positively correlated with sexual language and with use of swear words in the presence of their partner, but not in the presence of co-workers or children. Conclusions: Together, these results suggest that T may influence social behavior by increasing the frequency of words related to aggression, sexuality, and status, and that it may alter the quality of interactions with an intimate partner by amplifying emotions via swearing.