The solubility of lamotrigine was measured in aqueous mixtures of ionic liquid, 1-octyl-3-methylimidazolium bromide [OMIm][Br] up to 0.9 mass fraction at T = (293.2-313.2) K. The lambda-h and van't Hoff models with temperature dependency and Jouyban-Acree-van't Hoff, e-NRTL, UNIQUAC and Wilson models with temperature and solvent composition dependencies were used to correlate the experimental solubility data. The computed %ARDs show that the van't Hoff equation is better than lambda-h model and Jouyban-Acree-van't Hoff model has the best agreement with the experimental data and the order of % ARDs for the used models is, Jouyban-Acree-van't Hoff < e-NRTL < UNIQUAC < Wilson. Moreover, to understand the thermodynamic behaviour of studied solutions, apparent Gibbs energy, enthalpy and entropy of dissolution and mixing were estimated based on the van't Hoff and Gibbs energy equations. Thermodynamic analysis results indicate the strong solute-co solvent interactions between LTG and the ionic liquid and main contribution of enthalpy for dissolution of LTG in the aqueous mixtures of ionic liquid. (C) 2019 Elsevier Ltd.