Background: Thunbergia erecta (Acanthaceae) is the most abundant medicinal plant in different parts of Bangladesh where it is known as “nilghonta”. It has been used as traditional medicine for insomnia, depression and anxiety management. However, no scientific evidence of T. erecta belonging to neuropharmacological activity has been reported. The aim of present study was to investigate in vivo sedative and anxiolytic activities of methanol extract from the leaves of T. erecta in Swiss Albino mice. Methods: Sedative activity of METE was investigated using open field, hole cross and thiopental sodium-induced sleeping time test model whereas anxiolytic activity was screened by elevated-plus maze, light-dark box, hole-board and marble-burying test method in mice at 200 and 400 mg/kg doses. The acute toxicity study and phytochemical analysis of METE also carried out. Diazepam used as the positive control for the following behavioral pharmacology test. Results: METE exhibited significant (p < 0.001) sedative effect by decreasing the number of (square and hole) crossed by mice in open field and hole cross tests in a dose-dependent (200 & 400 mg/kg) manner. In thiopental sodium-induced sleeping time test METE significantly (p < 0.001) shortened the latency period and prolonged the sleeping time in a dose dependent (200 & 400 mg/kg) manner. Elevated plus maze (EPM) and light-dark box test results explicated that mice preferred open arms and light part instead of close arms and dark part significantly (p < 0.001). In hole-board and marble-burying test METE (200 & 400 mg/kg) reduced (p < 0.001) the number of head dipping and number of marble burying respectively. However, Phytochemical screening of METE revealed the presence of flavonoids, glycosides, tannins saponin, carbohydrates and alkaloids. Conclusion: The experimental result indicates T. erecta contains phytoconstituents that possess sedative and anxiolytic activity which traditionally used in insomnia, depression and anxiety management.