Several aluminium (Al) based MPEAs are reported to exhibit excellent corrosion and pitting resistance. Owing to a scarcity of detailed physical analysis, mechanistic aspects of the passivity of aluminium (Al) based MPEAs have not been adequately described to date. The complex thermo-kinetic interfacial processes that govern the dissolution behavior of MPEAs are challenging to ascertain; and herein an in-situ atomic emission spectroelectrochemistry (AESEC) method was used to investigate dissolution and passivation behavior. Along with AESEC analysis, the formation and evolution of the passive films were studied using X-ray photoelectron spectroscopy (XPS), Mott-Schottky analysis and equilibrium thermodynamics.