  We present an analysis of compactifications of the type IIB superstring on
AdS_5 x S^5 / \Gamma, where \Gamma is an abelian cyclic group. Every \Gamma
=Z_n of order n<= 12 is considered. This results in 60 chiral models, and a
systematic analysis with n<8 yields four containing the minimal SUSY standard
model with three families. One of these models extends to an infinite sequence
of three-family MSSMs. We also give a lower bound on the number of chiral
models for all values of n.
