The mouse accessory olfactory system (AOS) is crucial for detecting chemosensory signals during social interactions among conspecifics. The vomeronasal organ serves as the peripheral sensory structure of this system, and sensory information is transmitted through the vomeronasal nerve to the accessory olfactory bulb (AOB). The AOB consists of mitral cells (projection neurons) and local interneurons, including granule cells and periglomerular cells (PGCs). Vomeronasal sensory neurons send excitatory synaptic input to AOB mitral cells through multiple glomeruli, which are surrounded by PGCs. However, the specific physiological function(s) of PGCs as well as whether they form a homo- or heterogeneous neural population remains unknown. Here, we investigate the biophysical properties of PGCs using whole-cell patch-clamp recordings from visually identified PGCs in acute mouse AOB slices. To detail cell type-specific features, we analyze passive and active membrane properties, voltage-activated currents, and action potential firing. Our findings reveal unique characteristics of PGCs, providing initial insights into their physiological properties within the mouse AOB. We demonstrate that, given their large input resistance, PGCs are highly sensitive to electrical stimulation. With fast action potential kinetics, PGCs discharge at high frequencies. In addition, voltage-dependent potassium, sodium, and calcium currents display distinct activation and inactivation properties. Our results provide first insight into physiological characteristics of an elusive AOB neuron population. Ongoing research in this field will further enhance our understanding of the sensory processing principles in the AOB network.