Background: Oxidative stress is a key driver in the pathogenesis of oxidative-stress associated diseases, notably streptozotocin (STZ) induced-diabetes which is typically producen progressive pancreatic beta-cell destruction. Chia seeds (Salvia hispanica L.) are rich sources of plant polyphenols and omega-3 fatty acids that have antioxidant properties, but whether chia can protect against STZ-mediated beta-cell injury in rabbits had yet to be shown. The aim of the present study was to investigate the protective and therapeutic efficacy of chia seed ethanolic extract (CSEE) on pancreatic β-cell integrity, antioxidant status and some key biochemical indices in STZ- induce diabetic rabbits. Materials and Methods: Fourty male New Zealand White rabbits were randomly divided into four groups (n = 10 each): Group I (negative control, healthy), Group II (positive control STZ-induced diabetes) group III (CSEE treatment, oral at 400 mg/kg/day), and Group IV (CSEE prevention with STZ). A single intravenous injection of STZ (65 mg/kg) was performed to induce the diabetes. Animals were observed for 8 weeks. Both serum glucose, insulin, total antioxidant capacity (T-AOC), malondialdehyde (MDA), amylase and lipase were assayed. Histopathological examination of the pancreatic tissues. Results: Fasting blood glucose, MDA, serum amylase and lipase were significantly higher (p < 0.001)—whereas insulin and T-AOC were lower compared with healthy controls for STZ-induced diabetic rabbits. CSEE treatment significantly attenuated these parameters in the direction of normalization (p < 0.05). Histopathological examination showed abundant necrosis of islets, vacuolation in beta cells, and inflammatory infiltration in the diabetic group but were significantly alleviated in CSEE-treated animals. Conclusion: The ethanolic extract of chia seed protects the antioxidant and cytotoxic stress in STZ-induced diabetic rabbits, demonstrating its potential value as a natural adjunct to diabetes mellitus.