Magnesium (Mg) alloys, possessing good thermal and electrical conductivity, low density, recyclability, high specific strength, and excellent damping capacity, are regarded as one of the most promising light metallic materials. Mg alloys are also known as the “inexhaustible green light engineering material” compared with steel, aluminum, copper, and engineering plastics, providing some important applications in communications, automotive, defense, aerospace, and biomedical industries. However, the low electrode potential causes poor corrosion resistance in the environment of moist air, sulfur, and marine atmosphere. And thus, the corrosion and protection technology of Mg and its alloys is listed as an important research topic in this field. In this Research Topic, the latest research papers on corrosion and protection of Mg and its alloys are collected to provide a platform for researchers and readers to understand the recent developments in this field. Good use of this platform could improve the international research level in corrosion and protection of Mg and its alloys and promote the “green, safe, life-extending and smart” anti-corrosion technology and expand the application range of Mg and its alloys. High-quality Original Research and Review articles in this field are all welcome for submission to this Research Topic. Research interests include but are not limited to the following areas: • Corrosion behaviors and mechanisms • Surface treatment technology • Biodegradable medical applications • High-temperature oxidation • Inhibitors for Mg and its alloys • New monitoring, evaluation, simulation, and prediction methods