The solubilities of L-valine, L-isoleucine, L-methionine, and L-threonine in water + tert-butanol mixed solvent were measured at temperatures from 283.15 to 328.15 K. It was found that the solubility of four amino acids in water + tert-butanol was a function of temperature and solvent composition and increased with the increase in temperature and water mole fraction in binary solvent. Solubilities were correlated with the Jouyban-Acree model, and the results showed that the calculated values of the Jouyban-Acree model were in good agreement with the experimental solubility.