Abstract. We prove the following generalization of the classical ShephardTodd-Chevalley Theorem. Let G be a finite group of graded algebra automorphisms of a skew polynomial ring A := kp ij [x 1 , · · · , xn]. Then the fixed subring A G has finite global dimension if and only if G is generated by quasireflections. In this case the fixed subring A G is isomorphic a skew polynomial ring with possibly different p ij 's. A version of the theorem is proved also for abelian groups acting on general quantum polynomial rings.