The growth of wurtzite ZnO on cubic MgO (001) substrates by molecular beam epitaxy is reported. ZnO epilayers exhibit the nonpolar m-plane orientation based on x-ray diffraction and transmission electron microscopy analysis. Comparative studies of ZnO grown by pulsed laser deposition on MgO (001) result in preferred growth in the polar c-plane orientation. Investigation by high resolution transmission electron microscopy confirms an abrupt ZnO/MgO interface and monolayer spacing consistent with m-plane growth of ZnO. X-ray diffraction pole figures indicate two preferred rotational domains in-plane with a twist angle of 30 degrees. (C) 2008 American Institute of Physics.