The study of the influence of temperature on the carrier-mediated transport through synthetic ion-exchange membranes has been undertaken. Quantitatively, the effects of temperature on the concentration gradient dependent facilitated transport of boric acid through an anion-exchange membrane (IONAC 3475 XL) in its borate form has been investigated. It has been observed that there is an enhancement in transport when the temperature of the two compartments under study is increased uniformly (isothermal systems), and for a given average temperature, when the temperature of the downstream compartment is increased relatively to the uphill compartment (non-isothermal systems). Transport is diminished when the temperature gradient is reversed. These results have been explained on the basis of membrane conductivity and boron capacity variations with temperature thanks to the Van't Hoff law, which is encountered in classical thermodynamics. The conclusion is that the enhancement of transport is due to the facilitation of the decomposition of polyborate complexes as the temperature rises.