The softening behavior of squeeze cast Mg-Li-Al and Mg-Li-Al-Zr alloys have been investigated. The highest hardness values of Mg-Li-Al and Mg-Li-Al-Zr alloys were obtained after solution treatment at $400^{circ}C$ for 1 hour. The hardness value, however, decreased as the aging temperature and time increased. Microstructural and calorometric analyses showed that quenched-microstructure changed from primary (${alpha}$ and ${eta}$)+secondary ${alpha}$ to primary(${alpha}$ and ${eta}$)+secondary ${alpha}+{ heta}$ after aging. The softening during aging was due to the coarsening of ${ heta}$ precipitates.