This Faraday Discussion brings together pioneers within this area in a cross-disciplinary manner by providing a platform to explore possible solutions to these challenges, while establishing a fundamental understanding of these novel materials. The synergy of combining theoretical and experimental experts to address these key questions will be brought out through the following four key sections: Synthesizing high-entropy alloy nanoparticles Advanced structural characterization of high-entropy alloy nanostructures Application of high-entropy alloy nanostructures in electrocatalysis Magnetic properties of high-entropy alloy nanostructures.