In this paper, the solubility of hydrochlorothiazide (HCT) was determined by using a laser method in pure solvents (methanol, ethanol, n-propanol, isopropanol, acetonitrile, ethyl acetate, water, 2 -butyl alcohol, 1-pentanol, and isobutyl alcohol) and binary solvent mixtures of methanol + water and acetonitrile + n-propanol at the temperatures ranging from 283.15 to 323.15 K in approximately 5 K intervals at atmospheric pressure. The solubility increases with increasing temperature in all pure solvents we chose. However, the solubility of HCT increases with increasing methanol content, and it increases first and then decreases with increasing acetonitrile content at constant temperature. The dissolving capacity of HCT ranks as methanol > acetonitrile > ethanol > ethyl acetate > n-propanol (isopropanol) > 2 -butyl alcohol (isobutyl alcohol) > 1-pentanol > water. The experiment data were well correlated with the modified Apelblat equation, lambda h equation, NRTL equation, and modified Jouyban-Acree model.