Abstract: Background: Diabetes mellitus is a metabolic disease characterized by high levels of blood glucose caused due to deficiency of insulin secretion or insulin action. The inhibition of carbohydrate hydrolysing enzymes such as α-amylase may be an important strategy in the decreasing of postprandial blood glucose in patients with type II diabetes (T2DM). Teucrium barbeyanum is an important traditionally used medicinal plant in Libya to manage T2DM. Purpose: The objective of the present study was to investigate the antioxidant activity and the in vitro pancreatic α-amylase inhibitory effect of Teucrium barbeyanum. Methodology: The methanolic extract of Teucrium barbeyanum was analysed for its content of polyphenols and flavonoids and the antioxidant capacity of the extract was determined by DPPH radical scavenging method using ascorbic acid as a positive control. Finally, the inhibition potency on α-amylase was assayed by CNPG3 method using acarbose as a positive control. Results: The extract has high antioxidant (IC50 = 3.72±0.03 μL mL–1) and α-amylase inhibitory activities (IC50 = 16.51±0.83 μL mL–1) when compared to ascorbic acid (IC50 = 8.13±0.56 μL mL–1) and acarbose (IC50 = 27.24±1.04 μL mL–1), respectively. Conclusion: These findings showed that the methanolic extract of Teucrium barbeyanum possesses α-amylase inhibitory activity and antioxidant potency which may provide a good source for natural products and may be used in the development of a new oral hypoglycemic agent.