The voltage-induced magnetic anisotropy change of an ultrathin ferrimagnetic FeGd alloy has been characterized using V|Fe90Gd10|MgO|Fe magnetic tunnel junctions. The bias-voltage dependence of the magnetoresistance measurement reveals the voltage-induced anisotropy change in the V|Fe90Gd10|MgO junction. The magnetic anisotropy field change (ΔHk) in Fe90Gd10 is about twice that in Fe owing to the small net magnetization of the former. Therefore, employing ferrimagnetic materials is a promising option for voltage-controlled frequency-tunable spintronic devices.