Let V be a vertex operator superalgebra and G a finite automorphism group of V containing the canonical automorphism such that V^G is regular. We classify the irreducible V^G -modules appearing in twisted V-modules and prove that these are all the irreducible V^G -modules. Moreover, the quantum dimensions of irreducible V^G-modules are determined, a global dimension formula for V in terms of twisted modules is obtained and a super quantum Galois theory is established. In addition, the S-matrix of V^G is computed.