The oxidation of multicomponent metal alloys, A_xB_yC_1-x-y, is a kinetically complex process that is not fully understood for many systems. As a result the design of oxidation-resistant alloys typically requires an empirical determination of the optimal composition. The comprehensiveness with which prospective alloy composition spaces, (x,y), can be screened has conventionally been limited by the time required to prepare and test large numbers of single-composition alloy samples. We have pioneered the development and use of high-throughput methods to study the composition dependence of alloy oxidation using composition spread alloy films (CSAFs), i.e. alloy thin films containing lateral gradients in composition. By analyzing different locations across the surface of a single, oxidized CSAF with spatially resolved characterization techniques (e.g. energy-dispersive X-ray spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy), we can screen oxidation behavior across a continuous range of alloy compositions, x = 0 → 1 and y = 0 → 1-x. We have used this concept to identify continuous boundaries dividing regions of composition space exhibiting different degrees of oxidation resistance for the ternary Al_xFe_yNi_1-x-y alloy system. Our current work applies similar approaches to study oxidation resistance in quaternary Al-Fe-Ni-Cr steels used in many industrially important alloys. Our high-throughput studies reveal in unprecedented detail how changes in composition influence oxidation resistance, and they offer important fundamental insights into the mechanisms of multicomponent-alloy oxidation.