The transesterification of dimethyl terphthalate by ethylene glycol was studied under conditions designed to yield bis (${eta}$-hydroxyethyl) terephthalate as the primary product. The reaction in the presence of seven kind of metal acetate catalyst appeared more likely to follow a machanism of single second-order reaction. The data are consistent with single second-order reaction expressed in terms of the amount of methanol as a function of time, but are not sufficiently consistent with single first-order kinetics to explain the mechanism.