Inula species grown in Lebanon are known to have beneficial effects in improving human health. Several Inula species are used in traditional medicine as expectorants, antitussives, diaphoretics, antiemetics, and bactericides. In this study, different extracts of two Lebanese Inula species [Asteraceae], Inula viscosa [I. viscosa] and Inula vulgaris [I. vulgaris] aerial parts, were investigated for their in vivo and in vitro antioxidant and antidiabetic potential. Since increased oxidative stress has been linked to a shortening of life span, the antioxidant effect was studied due to the increased rate of oxidative damage during diabetes. Antioxidant activities of various extracts of the plant parts were measured using in vitro quenching of diphenyl-2-picrylhydrazyl free radical [DPPH radical scavenging assay] and in vivo assessment of catalase level in serum of alloxan-induced diabetic mice [6 groups, 3 mice/group]. The effect of various Inula spp. under investigation was studied for their acute [6 h] and subacute [8 days] potential on blood sugar level in alloxan-induced diabetic mice. I. viscosa and I. vulgaris have shown very promising antidiabetic and antioxidant effects, especially in vivo. Different extracts have demonstrated some variations in their antioxidant activities, due to difference in their total phenolic contents. It is highly important to consider Inula species in management of chronic diseases like, diabetes.