We report an electro-optically[EO]tunable microdisk laser fabricated on the erbium[Er3+]-doped lithium niobate on insu-lator[LNOI]substrate.By applying a variable voltage on a pair of integrated chromium[Cr]microelectrodes fabricated near the LNOI microdisk,electro-optic modulation with an effective resonance-frequency tuning rate of 2.6 GHz/100 V has been achieved.This gives rise to a tuning range of 45 pm when the electric voltage is varied between-200 V and 200 V.