Albizia myriophylla (ABZ) is a plant used in Thailand and Peninsular Malaysia for the treatment of diabetes mellitus type II. The antioxidant activities of ABZ have been suggested as one of the mechanisms for the observed beneficial effects. Hence, this study examined the phenolic, flavonoid, and saponin contents and antioxidant activity from methanol extract (ME) and its derived fractions hexane (HE), chloroform (CE), ethyl acetate (EAE), butanol (BE), and aqueous fraction of the bark of ABZ (AE). Amongst the extracts, EAE showed the highest total phenolic content of about 0.77 mg of gallic acid equivalent/g of extract (mg GAE/mg). However, the highest flavonoid content was detected in HE at 1.04 µg retinol equivalent ((RE)/g extract), while the saponin content was highest in CE at 1.1 µg diosgenin equivalent ((DE)/g extract). In 1,1-diphenyl-2-picrylhidrazyl (DPPH) radical scavenging test, EAE at 100 µg/mL had the highest percentage of inhibition of about 72.55%. 2-2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS radical scavenging test) showed BE had the highest percentage of inhibition at 100 µg/mL at 82.91%. Ferric reducing antioxidant power elucidated BE as having the highest percentage of inhibition which was 86.04% followed closely by ME at 85.90%. Thus, the different extracts of ABZ displayed various antioxidant capacity with probable free radical scavenging activity, which may be useful for the treatment of chronic inflammatory related metabolic diseases, such as diabetes and obesity.