X‐ray absorption spectra at the Zr‐, Y‐, and Nb‐K edges of ZrO2‐YNBO4 solid solutions have been measured at 10 K to determine the local atomic structures. Both Y and Nb cations substitute for Zr in the cation network but maintain rather different local oxygen coordination from Zr. In tetragonal zirconia solid solutions, Y adopts a YO8 structure with a bond length of 2.32 Å. This is the same as the structure found in ZrO2–Y2O3, solid solutions, confirming our previous conclusion that Y is not associated with oxygen vacancies. Nb has an NbO4 structure with a bond length of 1.90 Å. This is shorter than the Zr–O, distance of 2.10 Å. The strong Nb–O coordination increases the bonding disparity between Zr–O layers, thus increasing tetragonality. This is similar to the trend previously established for ZrO2‐GeO2 solid solutions. Severe distortion of neighboring cations around the undersized Nb, similar to that previously found for undersized Fe3+ and Ga3+, is also observed. At higher temperatures, local Y–Nb cation ordering occurs at a concentration below the solubility limit, similar to the Zr–Ge ordering reported previously. This cation ordering mechanism allows the charge‐compensating Y‐Nb pair to stabilize the tetragonal structure but increase tetragonality.