The equilibrium solubility of sulfanilamide is determined in 12 mono solvents and 4 binary solvent mixtures with temperatures ranging from T = 278.15 to 318.15 K. The sulfanilamide solubility increases with increasing temperature in all mono solvents and binary mixtures and increases with the increase in acetone mass fraction and temperature. The solubility of sulfanilamide is the highest in acetone and the least in toluene among the mono solvents. The order of solubility in mono solvents is toluene < ethyl acetate < 1octanol < water < benzene < 1-butanol < 2-butanol < 2propanol < 1-propanol < ethanol < methanol < acetone. The experimental solubility in mono solvents can be well correlated using several thermodynamic models such as a modified Apelblat model, the Ah equation, and van't Hoff model; simultaneously, the binary solvent mixtures can be well correlated using the models such as a modified Apelblat model, the van't Hoff Jouyban Acree model, Apelblat Jouyban Acree model, and CNIBS/R K model.