Abstract: Epilepsy an important CNS (Central Nervous System) problem that about 1% f world’s population suffer of it. The aim of study was to evaluate of anticonvulsant effect of hydroalcoholic extract of Lavandula officinalis. In this study, anticonvulsant activity of the hydroalcoholic extract of Lavandula officinalis (L. officinalis) was studied against chemoconvulsant-induced seizures in male mice. Lavandula officinalis (100, 200, 400, 600 and 800 mg kg-1), diazepam (0.15 mg kg-1) and normal saline (10 mL kg-1) were injected intraperitoneally, respectively in different groups of mice, 30 min before nicotine (5 mg kg-1 i.p.). The onset time intensity and duration of convulsions and the percentage of death were recorded. Also the time-response (0, 15, 30, 45, 60 min before nicotine injection) for most effective dose of plant extract (600 mg kg-1) was investigated. The results showed that hydroalcoholic extract of Lavandula officinalis had anticonvulsant effect. The most effective dose of plant extract was 600 mg kg-1. In time-response study for the most effective dose of extract (600 mg kg-1), the onset, duration and intensity of convulsion significantly (p<0.05) increased, decreased and decreased, respectively for all tested times. The best response observed in 30, 45 and 60 min. The results showed significant anticonvulsant effect for hydroalcoholic extract of Lavandula.