Lavandula stoechas grows naturally in most parts of the world specifically south France, the Mediterranean region and Torento. The plant has various pharmacological properties including analgesic, anti-inflammatory, antidepressant, hypnotic, sedative and tranquilizer, muscle relaxant, anticonvulsant, antibacterial and antispasmodic. For studying the effectiveness of sedative, preanesthetic and anxiolytic effects of Lavandula stoechas in comparison with diazepam different groups of female Wistar rats with the same age and weight conditions received intraperitoneal injections of Lavandula stoechas (100, 200, 400 mg/kg, ip), diazepam (1.2 mg/kg, ip), dimethyl sulfoxide (DMSO) as a placebo with equal volume 30 minutes before assessing the sedative and preanesthetic effects (induced sleep duration by ketamine, 40 mg/kg, ip) and anxiolytic effects (using Elevated plus maze) and (Rotarod test). Statistical analysis of the results obtained represent a significant increase in sleep time induced with ketamine and also a significant increase in the time the rats spent in open arms of maze with high and low doses of Lavandula stoechas herbal extract (p<0.01). The result showed that herbal extract of Lavandula stoechas at 200 mg/kg has sedative, preanesthetic and anxiolytic effects.