  We discuss recent developments on the solution of the so-called
supersymmetric mu-problem in the context of heterotic orbifolds. In particular,
an approximate R symmetry can induce an admissible mu-term in Minkowski vacua
of orbifold models with the MSSM spectrum. A natural solution to the mu-problem
is also offered by explicit string-derived NMSSMs. These models help avoid the
fine-tuning of the MSSM.
