An injection molding apparatus having a nozzle which includes a first nozzle body segment, a second nozzle body segment, and a thermal barrier coupled between the nozzle body segments. The first nozzle body segment, the thermal barrier, and the second nozzle body segment define a melt channel through the nozzle for delivering a melt stream from a manifold channel of a manifold to a mold cavity. The thermal barrier substantially limits the heat flow from one nozzle body segment to the other, to thereby control the heat distribution along the melt channel.