A belt tensioning device comprises a base member; at least one tensioning arm which, relative to the base member, is pivotably supported around a pivot axis; a tensioning roller for tensioning the belt; a spring for resiliently supporting the tensioning arm; and a connecting assembly for connecting the tensioning arm to the base member, wherein the connecting assembly comprises at least two base member connecting portions and at least two tensioning arm connecting portions which are connected to one another by an insertion and rotational movement; wherein, between a first base member connecting portion and a first tensioning arm connecting portion a first contact surface region is formed which is greater than a second contact surface region which is formed between a second base member connecting portion and a second tensioning arm connecting portion.