This paper studies the electrochemistry of liquid eutectic gallium indium in aqueous sodium hydroxide solution. The work is motivated by a recent observation that electrochemical oxidation of liquid metal can significantly lower its effective interfacial tension. To identify possible electrochemical reactions that could contribute to the unique interfacial activity, we use a suite of voltammetry techniques. We identify six regimes: (1) Below open circuit potential, the liquid metal has a large metal-like interfacial tension since it lacks a conformal oxide layer due to the high pH. (2) Just above the circuit potential, electrochemical oxidation of gallium commences. The oxide species do not accumulate due to dissolution and the interfacial tension does not lower. (3) At slightly higher potential, a thin film forms on the surface and the current drops. This passivation of the surface may occur by formation of hydrolyzed Ga oxide. (4) At increased potentials, passivation breaks down and tension drops significantly. (5) Beyond passivation breakdown, electrochemical oxidation of gallium forms soluble gallium hydroxide species. The interfacial tension drops linearly in this regime. (6) At even higher potentials, the surface partially repassivates. Insights from this study may provide better electrochemical control of the interfacial tension of liquid metal, which is useful for creating forces to move and manipulate small volumes of the metal.