Cross laminated Timber (CLT) is commonly used as load-carrying, planar structural element for roofs, floors and walls. Most frequently it can be seen as beam-like structural element. Due to their high geometrical slenderness (h/ttot), the stability of CLT elements used as wall-shaped beam over a long span has to be taken into account. Within this paper, the determination of the torsional stiffness of CLT elements will be discussed and the verification process for lateral torsional buckling will be demonstrated on that basis according to ÖNORM B 1995-1-1 . Furthermore the derivation of the buckling differential equation is shown and the solutions for different support conditions are demonstrated. A practical design example will sum up the publication and demonstrate the application of the derived formulae.