The solubility of tris(hydroxymethyl)aminomethane (TRIS) in various mass fractions of ternary solvent mixtures of water + methanol +1-propanol at 293.2 K, 298.2 K, 303.2 K, 308.2 K, and 313.2 K was measured using a laser monitoring technique. The mole fractions of water in the ternary mixtures were between 0.90 and 0.17; the mole fraction solubility of TRIS ranged between 0.0150 and 0.1187. The generated data was mathematically represented by the combined models of Jouyban-Acree and van't Hoff, enabling the solubility to be expressed as a function of both ternary solvent compositions and temperatures. The back-calculated mole fraction solubilities agreed with the corresponding experimental values by an overall mean percentage deviation of 5.6%.