Creep resistance is a major requirement for the use of magnesium in automotive powertrain components that are currently made of aluminium or cast iron. This paper summarises various new magnesium alloys that have been developed in recent years for elevated temperature applications. The alloy development basis, mechanical properties, creep resistance, bolt-load retention characteristics, and microstructure of seven new alloy systems (Mg–Al–RE, Mg–Al–Ca, Mg–Zn–Al–Ca, Mg–Al–Ca–RE, Mg–Al–Sr, Mg–Si, and Mg–RE–Zn; where RE represents mischmetal rare earth elements) are critically reviewed. The potential applications of these alloys in automotive powertrains are also discussed.