The possibility of spontaneous breaking of CP symmetry by the expectation values of orbifold moduli is investigated with particular reference to CP-violating phases in soft supersymmetry-breaking terms. The effect of different mechanisms for stabilizing the dilaton and the form of the non-perturbative superpotential on the existence and size of these phases is studied. Models with modular symmetries which are subgroups of PSL(2, Z) , as well as the single overall modulus T case with the full PSL(2, Z) modular symmetry, are discussed. Non-perturbative superpotentials involving the absolute modular invariant j(T), such as may arise from F-theory compactifications, are considered.