Activating transcription factor 5 (ATF5) is a stress response transcription factor of the cAMP-responsive element-binding/ATF family. Earlier, we reported that ATF5 expression is up-regulated in response to stress, such as amino acid limitation or arsenite exposure. Although ATF5 is widely expressed in the brain and the olfactory epithelium, the role of ATF5 is not fully understood. Here, the olfactory bulbs (OBs) of ATF5-deficient mice are smaller than those of wild-type mice. Histological analysis reveals the disturbed laminar structure of the OB, showing the thinner olfactory nerve layer, and a reduced number of interneurons. This is mainly due to the reduced number of bromodeoxyuridine-positive proliferating cells in the subventricular zone, where the interneuron progenitors are formed and migrate to the OBs. Moreover, the olfaction-related aggressive behavior of ATF5-deficient mice is reduced compared to wild-type mice. Our data suggest that ATF5 plays a crucial role in mouse OB development via interneuron.