Background Stressful life experiences are associated with neurobehavioral abnormalities, such as anxiogenic-related depression and cognitive decline. Reportedly, adaptogens are well known to modulate stress-related responses and promote resilience. Objective This study aimed to assess the potential mechanisms and adaptogenic properties of diosgenin (DG), a phytosteroidal sapogenin with neuroendocrine protective effects, in chronic unpredictable mild stress (CUMS)-induced anxiogenic-depression and cognitive deficits in mice. Methods During the 21-day study, mice were divided into five groups, and were daily treated with 5% dimethyl sulfoxide (control and CUMS model), diosgenin (25 mg/kg and 50 mg/kg) or fluoxetine (10 mg/kg) orally, respectively, followed by 21-item CUMS paradigm exposure, except for the control group. Mice were examined for anxiety, depression and cognitive-like features using relevant neurobehavioral paradigms. Biomarkers of oxidative stress, nitrite level, pro-inflammatory cytokines (TNF-α, IL-6), acetylcholinesterase (AChE), glutamic acid decarboxylase (GAD), and monoamine oxidase-B (MAOB) were measured in the prefrontal cortex, striatum, and hippocampal regions of the brain. Also, adrenal hypertrophy, serum corticosterone and glucose levels as a measure of hypothalamic pituitary adrenal (HPA) axis involvement were examined. Results DG ameliorated CUMS-induced behavioral anomaly, as characterized by the increased duration of grooming bouts in the sucrose preference test; decreased duration of immobility in the tail suspension and forced swim tests; anxiolytic effects in the elevated-plus maze, hole-board, light/dark compartment tests, as well as cognitive impairments indexed by the Y-maze and object recognition tests were reversed by DG respectively. DG remarkably decreased adrenal hypertrophy and elevated serum levels of corticosterone and glucose in CUMS mice. Conclusion Conclusively, DG exhibits antidepressant-like and anxiolytic-like actions with memory enhancement in the CUMS mouse model, and thus could serve as an alternative agent for the management of depression and anxiety associated with cognitive decline in clinical settings.