Basal amygdala (BA)-to-nucleus accumbens (NAc) projection neurons are integral to the circuitry of emotional processing. Recent studies have addressed whether neurons in this population(s) respond to reward, aversion or both emotional valences, but the focus has been on processing of physical emotional stimuli. Here, we extend this to salient social stimuli, whose processing is essential for the whole the animal kingdom and vital for maintaining individual physical and mental health. In male mice, an iterative study was conducted into engagement of BA-NAc neurons in response to social reward (SR, estrous female) and/or social aversion (SA, aggressive-dominant male). In BL/6J mice, a comparable number of anteroposterior intermediate BA (int- BA)-NAc neurons expressed c-Fos in response to SR or SA, while the posterior (post-)BA-NAc neurons were predominantly responsive to SA. In Fos-TRAP2 mice, exposure to successive presentation of SR-SA or SA-SR, followed by assessment of tdTomato reporter and/or c-Fos expression, demonstrated that many int-BA-NAc neurons were monovalent for social stimuli, i.e. they expressed c-Fos only in response to SR or SA. In freely moving BL/6J mice exposed to SR, bulk GCaMP6 fibre photometry provided confirmatory in vivo evidence for engagement of int-BA-NAc neurons during social and sexual interactions. Therefore, populations of BA-NAc glutamate neurons are engaged by salient rewarding and aversive social stimuli in a topographic and valence-specific manner; this novel evidence contributes to the overall understanding of the roles of this pathway in the circuitry of socio-emotional processing.