N-doped, Li-doped, and Li-N doped Zn0.89Mg0.11O thin films have been prepared by pulsed laser deposition. Hall-effect measurements indicate that the doping technique plays an important role in the p-type behavior of ZnMgO. Li doping produces high-resistivity p-type ZnMgO films, whereas N doping produces ZnMgO films with indeterminate carrier type. In contrast, Li-N codoping results in low resistivity and stable p-type ZnMgO films. The enhancement by Li and N coincorporation is investigated by secondary ion mass spectroscopy and is possibly responsible for the good p-type conduction in Li-N dual-acceptor doped Zn0.89Mg0.11O.