<p>Social valence is the directional emotional significance affiliated with social experiences. Maladaptive social information processing has been linked to mood disorder susceptibility, which is more prevalent in women. To determine whether there are sex differences in social valence processing, we employed behavioral tasks that associated conspecific identity recognition with either positive or negative valence, as well as tasks in which valence information originated from social targets. Male mice demonstrated identity recognition regardless of social valence. While male and female mice performed similarly in the positive social valence task, female mice did not show identity recognition following the negative social valence task. In vivo calcium imaging of the dorsal CA1 further revealed sex differences in negative social valence processing with reduced hippocampal representation of social information in female mice. Finally, enhancing dorsal CA1 neuronal activity by ampakine rescued identity recognition in female mice. These results suggest that sex differences in social valence processing may contribute to the heightened vulnerability to social stress-related mood disorders in women.</p>