The article reviews the current progress in the research of heat-resistant magnesium (Mg) alloys, emphasizing their importance in various fields such as aerospace, automotive, and electronics. The high-temperature mechanical properties of commonly used commercial Mg alloys, like AZ91D, deteriorate significantly with increasing temperatures. To address this issue, extensive efforts have been made to develop heat-resistant Mg alloys through various approaches, including inhibiting the formation of thermally unstable phases and promoting the formation of thermally stable precipitates or phases through solid solution or precipitation strengthening. The review systematically introduces and discusses different alloy systems, including Mg–Al, Mg–Zn, and Mg–rare earth (RE), comparing their mechanical properties and strengthening mechanisms. It highlights the limitations and future prospects of these heat-resistant Mg alloys to broaden their potential applications. The deformation mechanisms at high temperatures, such as dislocation slips, twinning behavior, and grain boundary sliding, are also discussed. Dislocation slips, particularly prismatic and pyramidal slips, become dominant at higher temperatures, enhancing the ductility of Mg alloys. Twinning, while less significant at high temperatures, remains an important mechanism for coordinating deformation. Grain boundary sliding, which decreases with temperature, is another crucial deformation mode. Overall, the review provides a comprehensive overview of the current state of heat-resistant Mg alloy research, identifying key trends, challenges, and future directions for further development.The article reviews the current progress in the research of heat-resistant magnesium (Mg) alloys, emphasizing their importance in various fields such as aerospace, automotive, and electronics. The high-temperature mechanical properties of commonly used commercial Mg alloys, like AZ91D, deteriorate significantly with increasing temperatures. To address this issue, extensive efforts have been made to develop heat-resistant Mg alloys through various approaches, including inhibiting the formation of thermally unstable phases and promoting the formation of thermally stable precipitates or phases through solid solution or precipitation strengthening. The review systematically introduces and discusses different alloy systems, including Mg–Al, Mg–Zn, and Mg–rare earth (RE), comparing their mechanical properties and strengthening mechanisms. It highlights the limitations and future prospects of these heat-resistant Mg alloys to broaden their potential applications. The deformation mechanisms at high temperatures, such as dislocation slips, twinning behavior, and grain boundary sliding, are also discussed. Dislocation slips, particularly prismatic and pyramidal slips, become dominant at higher temperatures, enhancing the ductility of Mg alloys. Twinning, while less significant at high temperatures, remains an important mechanism for coordinating deformation. Grain boundary sliding, which decreases with temperature, is another crucial deformation mode. Overall, the review provides a comprehensive overview of the current state of heat-resistant Mg alloy research, identifying key trends, challenges, and future directions for further development.