This chapter deals with basement walls under lateral earth pressure. It discusses the design of basement walls under horizontal earth pressure. Such walls need to carry horizontal loads from the adjacent soil. The design of basement walls is based on the arch model developed by Mann & Bernhardt, which uses the global safety concept. For the structural design of external basement walls, EN 1996-3 allows a simplified verification method based on the design of an arch. The basement slab has to be constructed as a bracing slab and has to be able to support the forces resulting from the earth pressure. DIN EN 1996-1-1/NA contains supplementary regulations of the design of basement walls with variable earth pressure coefficient. In order to ensure the load bearing capacity of basement walls under predominant bending loads due to horizontal earth pressure, a certain minimal vertical load is required.