ASandwich sandwich is a structure that is made up of two so-called facesheets and a so-called core (Fig. 19.1). Sandwiches are generally designed in such a way that the facesheets exhibit high stiffness and strength, whereas the core has significantly weaker properties. If the sandwich is subjected to a bending load, the facesheets are significantly involved in the transfer of the bending moments, namely in the form of tensile and compressive forces in the facesheet plane. However, the core is responsible for the transfer of shear stresses and is generally not or only very little involved in the transfer of bending moments. A sandwich therefore obviously has a very clear division of tasks between the individual components, which will be discussed in detail later on. We begin this chapter with a fundamental discussion of the load-bearing behaviour of sandwich structures. Afterwards, the considerations are detailed using the example of an orthotropic sandwich panel. We end the chapter by analysing a completely arbitrary sandwich structure.