The solubility of ammonium metavanadate (NH4VO3) in ammonium salt solution is significant for the precipitation of NH4VO3from the vanadium-containing solution. The solubilities of NH4VO3 in the (NH4)2SO4–H2O, NH4Cl–H2O, and (NH4)2SO4–NH3–H2O systems were measured using dynamic method in the temperature range from (298 to 343) K. The investigated concentration is up to 3.0 mol·kg–1, 2.5 mol·kg–1, and 5.2 mol·kg–1 for (NH4)2SO4, NH4Cl, and NH3, respectively. The solubility of NH4VO3 decreases sharply with the addition of (NH4)2SO4 or NH4Cl while the solubility of NH4VO3 in the mixed NH3 and (NH4)2SO4 (0.10 mol·kg–1) solution increases first and then levels off with increasing NH3 concentration. The solubility product constant (KSP) of NH4VO3 was also determined using the standard-state thermodynamic data. The Bromley–Zemaitis model was applied to model the solubility of NH4VO3 in the systems mentioned above, and five pairs of new model parameters were obtained via the regression of the experimental solubili...