Context: Moringa oleifera is the famous plant that has been used as medicinal plant for diverse pharmacological activity. Aims: To evaluate the total phenolic, total flavonoid, quercetin content as well as the antioxidant activity of standardized extract of Moringa oleifera (Lamk) leaf, collected from three regions with different elevation. Materials and Methods: The leaves were extracted by maceration method using ethanol 96% and evaporated by rotary evaporator to obtain the viscous extract. The determination of total phenolic and total flavonoid were performed by spectroscopic method, while the quercetin concentration were determined by high performance liquid chromatography (HPLC). The antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Results: Ethanolic extracts of Moringa oleifera leaf from region with medium altitude (Sigi regency) showed higher total phenolic, total flavonoid, quercetin concentration and antioxidant activity than regions with low and high altitude (Parigi and Palu cities). Conclusion: This study reveals the potency of standardized extracts of Moringa oleifera growing in medium altitude (Sigi regency) to be developed as antioxidant herbal medicine.