This review provides a comprehensive overview of the fundamentals and recent advances in magnesium (Mg) alloy corrosion. Mg alloys are the lightest structural metallic materials, offering significant potential for reducing energy consumption in engineering systems. However, their widespread use is limited by issues such as corrosion vulnerability, poor formability, and low creep resistance. The review discusses recent research on Mg corrosion, including the application of modern methods to understand corrosion mechanisms, the development of an electrochemical framework for Mg corrosion, and the effects of alloying. It also covers atmospheric corrosion, biodegradable Mg alloys, and the role of various atmospheric gases and substances in Mg corrosion. The review highlights the importance of corrosion resistance in Mg alloys, particularly in biomedical applications and as battery electrodes. It also discusses protection strategies against atmospheric corrosion and the role of alloying in improving corrosion resistance. The review identifies knowledge gaps and future directions in Mg corrosion research, emphasizing the need for further investigation into the mechanisms of corrosion, the effects of alloying, and the development of corrosion-resistant Mg alloys. The review also discusses the use of advanced analytical techniques in Mg corrosion research, including electrochemical methods, localized electrochemical techniques, and non-electrochemical methods such as weight loss measurements and hydrogen collection. The review concludes with an outlook on future developments in Mg corrosion research, emphasizing the importance of understanding the mechanisms of corrosion and the development of corrosion-resistant Mg alloys.This review provides a comprehensive overview of the fundamentals and recent advances in magnesium (Mg) alloy corrosion. Mg alloys are the lightest structural metallic materials, offering significant potential for reducing energy consumption in engineering systems. However, their widespread use is limited by issues such as corrosion vulnerability, poor formability, and low creep resistance. The review discusses recent research on Mg corrosion, including the application of modern methods to understand corrosion mechanisms, the development of an electrochemical framework for Mg corrosion, and the effects of alloying. It also covers atmospheric corrosion, biodegradable Mg alloys, and the role of various atmospheric gases and substances in Mg corrosion. The review highlights the importance of corrosion resistance in Mg alloys, particularly in biomedical applications and as battery electrodes. It also discusses protection strategies against atmospheric corrosion and the role of alloying in improving corrosion resistance. The review identifies knowledge gaps and future directions in Mg corrosion research, emphasizing the need for further investigation into the mechanisms of corrosion, the effects of alloying, and the development of corrosion-resistant Mg alloys. The review also discusses the use of advanced analytical techniques in Mg corrosion research, including electrochemical methods, localized electrochemical techniques, and non-electrochemical methods such as weight loss measurements and hydrogen collection. The review concludes with an outlook on future developments in Mg corrosion research, emphasizing the importance of understanding the mechanisms of corrosion and the development of corrosion-resistant Mg alloys.