A belt tensioning device for a belt drive comprises a base member that is firmly connectable to a stationary component; at least one tensioning arm, which is pivotably supported relative to the base member around a pivot axis; a spring element, with which the tensioning arm is supported elastically in circumferential direction, wherein the ratio of the nominal diameter to the axial length of the spring element is larger than 3.0 in the mounted condition; and a tensioning roller for tensioning the belt, which is rotatably supported on the tensioning arm around an axis of rotation; wherein the base member and the tensioning arm are each at least partially made from plastic material.