Films of ZrO2-X2O3 where X = Al, In, and Sc and of ZrO2-SnO2 were deposited by simultaneous electron-beam evaporation of the respective metal oxides. Films deposited onto substrates at room temperature were initially amorphous, but were transformed and stabilized in either the tetragonal or cubic phases of ZrO2 by annealing at appropriate temperatures over certain ranges of compositions. In the case of the ZrO2-In2O3 system, for example, the substrate was heated to 300-degrees-C during deposition and the ZrO2 was recovered in the cubic phase for indium compositions varying between 3.5 and 11 at.%. However, in the ZrO2-SnO2 system, the as-deposited film remained amorphous (even though the substrate was held at 300-degrees-C). Results of the effect of composition on lattice parameters and phase stability are reviewed and discussed.