Oxytocin (Oxt) is a nonapeptide hormone primarily known for its roles in lactation and parturition. Research has recently shifted to understanding its functions in the brain, particularly in social behaviors. Oxt is synthesized by magnocellular neurons in the hypothalamus and released from the posterior pituitary. It acts through its sole identified receptor, Oxtr, which is widely distributed in the brain. Oxt is involved in various social behaviors, including social memory, attachment, sexual behavior, and aggression. It also plays a role in human bonding and trust. Disorders characterized by aberrant social interactions, such as autism and schizophrenia, may involve abnormal Oxt expression. The review discusses the structure, evolution, pharmacology, and distribution of Oxt and its receptor in the brain, as well as the sex differences in their expression. Gene inactivation studies in mice have further characterized Oxt's role in social behaviors. Oxt is crucial for social memory and recognition, facilitating pair bonding and parental care. It also influences sexual behavior and aggression. The review highlights the importance of Oxt in social interactions and its potential therapeutic applications.Oxytocin (Oxt) is a nonapeptide hormone primarily known for its roles in lactation and parturition. Research has recently shifted to understanding its functions in the brain, particularly in social behaviors. Oxt is synthesized by magnocellular neurons in the hypothalamus and released from the posterior pituitary. It acts through its sole identified receptor, Oxtr, which is widely distributed in the brain. Oxt is involved in various social behaviors, including social memory, attachment, sexual behavior, and aggression. It also plays a role in human bonding and trust. Disorders characterized by aberrant social interactions, such as autism and schizophrenia, may involve abnormal Oxt expression. The review discusses the structure, evolution, pharmacology, and distribution of Oxt and its receptor in the brain, as well as the sex differences in their expression. Gene inactivation studies in mice have further characterized Oxt's role in social behaviors. Oxt is crucial for social memory and recognition, facilitating pair bonding and parental care. It also influences sexual behavior and aggression. The review highlights the importance of Oxt in social interactions and its potential therapeutic applications.