Glued-in rods are important connecting and reinforcing elements in modern timber engineering used in new and existing timber structures. The complex stress distribution along the bondline between rod and wood depends on the type and properties of the adhesive and the type of load application. In this chapter, different models for the determination of the shear stress distribution along the bondline are discussed and their effects on the stress distribution and strength of the glued-in rod are evaluated. Important points on how to enhance the load-carrying capacity and reach best structural capacity, as well as the ductile failure behaviour, are discussed.