  We discuss the appearance of non-supersymmetric D6-brane GUT model
constructions. We focus on the construction of the first examples of flipped
SU(5) and SU(5) GUTS which have only the SM at low energy. These constructions
are based on 4D compactifications in Z3 toroidal orientifolds of type IIA with
D6-branes intersecting at angles.
