Persea americana has been widely utilized in the traditional parlance for the management of diseases. The present study investigates the in vitro antioxidant mechanism(s) as well as the active principles responsible for the acclaimed therapeutic potentials of the plant. Powdered leaves of Persea americana leaves was extracted in ethanol, methanol and water and assessed for their total phenolic and flavonoids contents following established protocols. Free radical scavenging activity against 2,2-diphenyl-1- picryl hydrazyl (DPPH) and nitric oxide (NO) radicals as well as the ferric reducing antioxidant potential (FRAP) were also determined. Moreover, structure and relative abundance of phytochemical constituents of the methanolic extract of Persea americana leaves was determined on gas-chromatography-mass spectrometer (GCMS). Results indicate that methanolic extract exhibited significantly higher DPPH and NO radical scavenging and ferric reducing power than aqueous and ethanolic extract. However, aqueous extract of the plant has the highest total phenolic and flavonoids content of the three extracts investigated. GC-MS chromatogram of the methanolic extract of Persea americana leaves reveals the presence of eighteen phytochemicals. Phytochemicals content of P. americana leaves depends on the extraction solvent, while its antioxidant activity is not only a function of amount of phenols and flavonoids but of the individual antioxidant capacity of the phytochemicals.