A Ba2Ge2TiO8single crystal is synthesized by the Bridgman method. The space group of Ba2Ge2TiO8is determined to beC2v21‐Iba2, where the lattice constantsa, b, andcare 12.30, 135.2, and 10.70 Å, respectively. The crystal includes a wedge‐shaped domain structure which resembles those observed in Gd2(MoO4)3and Rochelle salt. BothXandYplates have a large electromechanical coupling factor in a thickness shear mode,k15= 0.27 andk24= 0.31.