  We summarize some recent progress in constructing four-dimensional
supersymmetric chiral models from Type II orientifolds. We present the
construction a supersymmetric Standard-like Model and a supersymmetric GUT
model to illustrate the new features of this approach and its connection to M
theory on compact, singular G_2 holonomy spaces. The Standard-like model
presented is the first example of a three-family supersymmetic orientifold
model with the Standard Model as part of the gauge structure. We also discuss
the connection of how chiral fermions arise in this class of models with recent
results of M theory compactified on G_2 holonomy spaces.
