There is an increasing evidence that maternal immune activation can render the offspring more vulnerable to the impacts of peripubertal stress on behavioral abnormalities in adulthood. The aim of this study was to investigate the combined effects of maternal immune activation and peripubertal stress on depression-related behaviors in male and female offspring. Pregnant mice were treated with lipopolysaccharides (LPS) or vehicle, and then offspring were subjected to stressful conditions or left unstressed during peripubertal period. Four behavioral tests including novelty-suppressed feeding test, sucrose preference test, tail suspension test, and forced swim test were used to measure depression-related behaviors in offspring. The activity of hypothalamic-pituitary-adrenal (HPA) or - gonadal (HPG) axes were also evaluated by measuring basal and stress-induced corticosterone, testosterone and estradiol levels in the serum of offspring. Our findings revealed that mild maternal immune activation and peripubertal stress interacted synergistically to induce depression-related symptoms and HPA axis hyperactivity in male offspring, whereas no significant changes were observed in female offspring. We also found that this combination of environmental factors significantly decreased serum testosterone and estradiol levels in adult male and female offspring respectively. There were also significant correlations between behavioral parameters and hormones. Taken together, these findings show that the combination of two environmental risk factors can predispose the male offspring to increased depression-related symptoms in adulthood as compared to the females. This study suggests that the combination of maternal immune activation and peripubertal stress can alter depression-related behaviors and HPA axis function in a sex-dependent manner.