Here, we evaluated the antidiabetic and hypoglycaemic activities of Moricandia sinaica, a species of the Brassicaceae family, for the first time. The hypoglycaemic and antidiabetic activities of the M. sinaica shoot’s methanol extract (MOR-1), butanol fraction (MOR-2), and aqueous fraction (MOR-3) were examined against streptozotocin-induced diabetes model in albino Swiss mice. The mice were divided into eight groups (each group consisted of 6 mice). MOR-1 (100 and 200 mg/kg), MOR-2 (100 and 200 mg/kg), and MOR-3 (100 and 200 mg/kg) were administered to groups III, IV, V, VI, VII, and VIII, respectively, for 15 days (daily). The blood samples were haematologically and biochemically assessed at 0 days, 7 days, and 15 days. Mice in group I were kept untreated as control while group II was treated with glibenclamide as standard. Antidiabetic effects increased with MOR-1 and MOR-2 doses in a dose-dependent manner. MOR-2 treatment (200 mg/kg) yielded the best results (29.56% and 40.07% after 7 and 15 days, respectively) compared to the results obtained at zero days. MOR-2 (200 mg/kg) showed the greatest decline in glucose levels (27.67% and 41.13% after 7 and 15 days, respectively). The results concluded that M. sinaica exhibited potential hypoglycaemic activity.