Background: Newbouldia laevis Seem. (Bignoniaceae) is a woody tropical plant employed by traditional medicine practitioners (TMPs) in Nigeria in the treatment of various disease conditions, including central nervous system disorders. Objective: To evaluate the anticonvulsant, sedative-hypnotic, muscle relaxant and in-vitro antioxidant activities of the hydroethanol leaf extract of Newbouldia laevis (HNL). Materials and Methods: HNL (25–200 mg/kg, p.o.), distilled water (10 ml/kg, p.o.) or diazepam (3 mg/kg, p.o.) were administered 1 h before strychnine or picrotoxin-induced seizure, thiopentone-induced hypnotic, inclined plane and traction tests in mice. The in-vitro antioxidant activity of HNL was investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide, hydrogen-peroxide scavenging, lipid peroxidation and reducing power assays. The total antioxidant capacity, total phenolics and total flavonoids were also determined. Results: In the picrotoxin-induced convulsion test, HNL (100 mg/kg) increased the latency (p<0.05) and decreased the duration (p<0.001) of seizure. The extract was not effective in the strychnine-induced convulsion test. The extract at 100 and 200 mg/kg signigicantly increased the latency (p<0.001, 0.05 respectively) but not duration of sleep in the thiopentone-induced hypnosis test. In the inclined screen model, the extract at 100 mg/kg significantly reduced the post-treatment sliding latency (p<0.05) compared to the pre-treatment value. The total antioxidant capacity, total phenolics and total flavonoids were 42.65±0.16, 44.49±0.15 and 23.61±0.18 mg/100 g of standards equivalent respectively. HNL in a concentration-dependent manner scavenged reactive species in the in-vitro antioxidant tests. Conclusion: The findings in this study showed that HNL possesses anticonvulsant, muscle relaxant and antioxidant activities. This confirms the beneficial property of the extract in the treatment of seizures.