In the present study, abietic acid was evaluated for antidepressant-like activity in normal mice and chronic unpredictable mild stress (CUMS) –induced depressed mice. Swiss albino male mice were subjected to CUMS for 21 successive days. Abietic acid (7.5, 15, and 30 mg/kg, p.o.) and fluoxetine (20 mg/kg, p.o.) per se were given for 3 successive weeks to separate groups of normal mice and CUMS-induced depressed mice. Tail suspension test (TST) and sucrose preference test were employed to study the effect of the drugs on the depressive-like behavior of mice. CUMS produced depression-like behavior in mice. In TST, the immobility period was significantly decreased by abietic acid (30 mg/kg) and fluoxetine in normal mice as well as in CUMS-induced depressed mice as compared to their respective control groups. A decrease in sucrose preference due to CUMS was significantly restored by abietic acid (15 and 30 mg/kg) and fluoxetine. Locomotor activities of mice were not significantly changed by abietic acid and fluoxetine. Plasma nitrite, brain monoamine oxidase –A (MAO-A) activity, and brain malondialdehyde were significantly decreased; and brain catalase activity and reduced glutathione levels were significantly increased by abietic acid (15 and 30 mg/kg) and fluoxetine in both normal mice and CUMS-induced depressed mice. CUMS-induced increase in plasma corticosterone levels was significantly lowered by abietic acid (15 and 30 mg/kg) and fluoxetine. Abietic acid exerted significant antidepressant-like activity in both normal mice and CUMS-induced depressed mice possibly through mitigation of oxidative stress and decrease of brain MAO-A activity. Additionally, lowering of plasma corticosterone concentration by abietic acid in CUMS-induced depressed mice might also contribute to its antidepressant-like effect.