We investigate a possibility of constructing 6-dimensional gauge-Higgs unification models compactified on T^2/Z_N that have a custodial symmetry. We consider all simple groups whose ranks are two and three as a 6D gauge group, and find appropriate orbifold boundary conditions that realize a realistic field content in 4D effective theory for each gauge group. We also calculate the Higgs potential at tree level and discuss the Higgs mass. Our results are useful to construct realistic models.