A group contribution method is proposed to determine linear solvation energy relationship parameters (GC-LSER) in view of estimating the gas-to-ionic liquid partition coefficients and water-to-ionic liquid partition coefficients. Large sets of partition coefficients were analyzed using the Abraham solvation model to determine the contributions of 21 groups: 12 groups characterizing the cations and 9 groups for the anions. The derived equations correlate the experimental gas-to-ionic liquid and water-to-ionic liquid partition coefficient data to within 0.15 and 0.17 log units, respectively. The 21 group-parameters can he used to predict the partition coefficients of solutes in alkyl or functionalized ionic liquids with a good accuracy.