Human social behavior is a complex construct requiring a wide range of cognitive abilities and is critically impaired in numerous neuropsychiatric diseases. Living in complex social groups, rodents offer suitable models to elucidate neural processing of social cognition. Recently, a potential involvement of the subthalamic nucleus (STN) in rats’ social behavior has been pointed out. For example, we showed that STN lesions abolish the modulatory effect of the familiarity on the rewarding value of social stimuli, questioning the involvement of STN in peer recognition. In this study, we thus assess the effects of STN lesions and optogenetic manipulations on peer and object recognition. STN optogenetic inhibition, like lesions, impair social recognition memory, while STN optogenetic high-frequency (HF) stimulation leads to a specific alteration of social encoding memory. None of these manipulations seem to interfere with social investigation, objects recognition memory, nor social novelty preference. Finally, STN optogenetic inhibition, but neither HF-stimulation, nor lesions, leads to an alteration of the cage-mate recognition memory. Overall, these results show that physiological activity of STN is necessary for rats to show a proper social recognition memory performance and question the possible detrimental effects of STN deep brain stimulation on these processes in human patients.