The effect of a galia (Ga2O3) addition on the crystallographic phase evolution and the crystal growth behavior of zirconia (ZrO2) rich powder were investigated. Binary compositions of galia–zirconia powder (on the zirconia-rich side of the quasi-binary phase diagram) were obtained by the sol–gel method and calcined at different temperatures for 2 h. Rietveld refinement (FullProf program) was used to determine the crystallographic phase composition. Crystal size was approximated based on X-ray diffractions analysis combined with estimates of average crystal size obtained by processing high-resolution scanning electron microscopy images. The surface area of the powders obtained was measured via the Brunauer–Emmett–Teller method. Zirconia–galia sol–gel powders were found to form tetragonal or mixed tetragonal–monoclinic solid solution phases depending on both composition and calcination temperature. It was shown that galia suppressed crystal growth process in zirconia, producing finer nano-powders with higher surface area compared to pure zirconia.