For social species, normal social cognitive functions are essential for individuals to survive in a social group. Various neuropsychiatric disorders, including schizophrenia, autism and bipolar disorder are characterized by the impairments in social cognition. The hippocampus has been at the forefront of research in learning and memory for several decades. Hippocampal dysfunction contributes to learning and memory impairments as well as a range of social dysfunctions. However, precise contributions of different hippocampal sub-regions to differential aspects of cognitive functions remain unclear. This review first describes several key features of social abnormalities related to neuropsychiatric disorders, and then introduces the behavioral tasks used in animal models to assess each feature. Second, it gives a basic description of CA2 anatomy followed by an overview of its known functions. Third, it highlights a number of recent findings that associate the abnormalities of the hippocampal CA2 area and social dysfunctions in both animal models and human patients.