In this work, the aluminum-air battery performance is improved by adding nonionic surfactant (nonoxynol-9) to battery electrolyte (4.0 M NaOH). The efficiency of nonoxynol-9 is determined using hydrogen gas evolution and electrochemical measurements. The surface analysis is explored using scan electron microscope and energy dispersive X-ray spectroscopy. Battery performance is investigated at 20 mA cm−2. The results show that the battery performance is significantly improved by adding nonoxynol-9. This is due to the low corrosion rate of aluminum in 4.0 NaOH solution resulted from physical adsorption of nonoxynol-9 on aluminum surface. The surfactant suppresses the hydrogen gas evolution and increases the anode utilization and capacity density. The maximum inhibition efficiencies of nonoxynol-9 from hydrogen gas evolution and electrochemical measurements are 85.6% and 92.8%, respectively at 2.0 mM. Nonoxynol-9 behaves as a cathodic-type inhibitor and its adsorption complies with Freundlich type isotherm. The adsorption of surfactant on the aluminum surface is emphasized by surface analysis.