An ester composition including terephthalate compounds substituted with a non-hybrid and non-branch type alkyl group, a hybrid and branch type alkyl group, and a non-hybrid and branch type alkyl group, respectively by 0.5 wt% to 9.5 wt%, by 14.5 wt% to 43.8 wt%, and 46.7 wt% to 85 wt% based on the total weight of the ester composition, a method of preparing the same, and a resin composition including the same are provided. The ester composition has a short absorption time with respect to the resin and short fusion time and improves the processability of the resin composition. In addition, good physical properties may be provided when manufacturing a sheet and a compound such as a cable, an interior of a car, a film, a sheet, a tube, a wallpaper, a toy, a flooring material, and the like.
