The corrosion control of aluminum alloy in HCl medium using Ocimum gratissimum (OG) leaves extract was investigated. Thermometric, gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopic techniques were employed in the corrosion control study. The leaves extract of Ocimum gratissimum was characterized by Fourier Transform Infrared (FTIR) spectroscopy and Gas Chromatography-Mass Spectroscopy (GC-MS). The FTIR spectrophotometer was also used to analyze the corrosion product for the identification of the functional groups responsible for the corrosion control process. The corroded aluminum alloy was studied using Scanning Electron Microscopy (SEM). It was observed that stretched N-O, C-H, S-S, C=O, N-H, C-Cl, C-O, O-H were the predominant functional groups responsible for the corrosion inhibition process. There was a synergy among the functional groups and molecular compounds of the extract in the corrosion inhibition process. Quadratic model was adequate for the description of the Inhibition Efficiency (IE) as a function of the considered factors of the inhibition process. Optimum IE of 80.09% at acid concentration of 1.1 M, inhibitor concentration of 1.3 gm/l, temperature of 312 K and time of 6 h was obtained. The plant extract was identified as mixed-type inhibitor that can control both the anodic and cathodic corrosion.