The structures of complexes of ZrIVand oxydiacetate (ODA2−) in aqueous solutions of pH 0–7 were investigated with the use of 1H, 13C, and 17O NMR spectroscopy. Equilibria of mononuclear [Zr(oda)]2+, [Zr(oda)2], and [Zr(oda)3]2−complexes have been observed. In all complexes ODA2−is bound in a tridentate fashion through the two carboxylate groups and the ether oxygen. No di‐ or oligonuclear species containing ODA2−were observed. An excess of free ZrIVremains in solution, probably as a result of weak electrostatic interactions between negatively charged Zr–ODA complexes or free ODA2−and a positively charged cyclic tetranuclear hydroxy zirconium complex. CP‐MAS 13C NMR spectra of solid compounds isolated from the samples indicated that the structures of the [Zr(oda)2] and [Zr(oda)3]2−complexes in solution are similar to those in the solid state. This is corroborated by the single‐crystal X‐ray structure of Na2[Zr(oda)3]⋅5.5 H2O, which was obtained from a solution containing exclusively the [Zr(oda)3]2−complex. In this structure ZrIVis nine‐coordinate with the three ODA2−ligands bound in a tricapped trigonal prismatic geometry. The negative charge of this [Zr(oda)3]2−complex is balanced by two Na+ions, one of which is on a center of symmetry between Δand Λenantiomers of [Zr(oda)3]2−. This Na+is octahedrally coordinated to six (non ZrIV‐bound) carboxylate oxygen atoms of six different [Zr(oda)3]2−units.