Objective To evaluate Brachychiton acerifolius leaf extracts as antidiabetic potential agent and to identify the main active constituents using bioactivity guided fractionation. Methods In vitro antioxidant activity was evaluated for B. acerifolius different extracts using DPPH assay and vitamin C as control. Antidiabetic activity was then determined using STZ-induced rats treated daily with ethyl acetate and 70% ethanol leaf extracts for 4 weeks at a dose of 200 g/kg body weight against gliclazide reference drug. Blood glucose, α-amylase, lipid profile, liver function enzymes and oxidative stress markers were assessed along with histopathological study for liver and pancreatic tissues. Isolation and structural elucidation of active compounds were made using Diaion and Sephadex followed by spectral analyses. Results The results indicated that ethyl acetate and ethanol leaf extracts exhibited the strongest antioxidant activity compared to that of vitamin C (IC