<p>Over the past two decades, high-entropy alloys (HEAs), also referred to as complex concentrated alloys (CCAs) or multi-principal element alloys (MPEAs), have garnered considerable attention due to their unique structural features and exceptional mechanical performance, including impressive resistance to oxidation, corrosion, and elevated temperatures. Nonetheless, most HEAs developed thus far are based on heavy constituent elements, resulting in high densities that limit their suitability for weight-critical applications. To address this, recent efforts have shifted towards creating lightweight HEAs (LWHEAs) to enhance energy efficiency. Within this category, magnesium-bearing HEAs are especially attractive due to their inherently low densities; however, a comprehensive understanding of these systems remains lacking. This work presents a critical evaluation of advancements in the production and development of LWHEAs, paying particular attention to systems with substantial magnesium additions. It offers a systematic analysis of synthesis methods, design philosophies, microstructural development, mechanical characteristics, and corrosion behavior of Mg-containing HEAs as documented in existing literature. The review concludes by highlighting promising future research avenues and suggesting directions for further exploration in this nascent field.</p>