  We study the possibility of constructing the NMSSM from the heterotic string.
String derived NMSSMs are much more rare than MSSMs due to the extra
requirement that there exist a light singlet which couples to the Higgs pairs.
They share the common feature that the singlet self-interactions are typically
suppressed, leading to either the "decoupling" or the Peccei-Quinn limit of the
NMSSM. In the latter case, the spectrum contains a light pseudoscalar which may
be relevant to the MSSM fine-tuning problem. We provide a Z_6 heterotic
orbifold example of the NMSSM with approximate Peccei-Quinn symmetry, whose
origin lies in the string selection rules combined with our choice of the
vacuum configuration.
