Embodiments of multi-substrate thermal management apparatus are provided herein. In some embodiments, a multi-substrate thermal management apparatus includes a plurality of plates vertically arranged above one another; a plurality of channels extending through each of the plurality of plates; a supply manifold including a supply channel coupled to the plurality of plates at first locations; and a return manifold including a return channel coupled to the plurality of plates via a plurality of legs at second locations, wherein the supply and return channels are fluidly coupled to the plurality of channels to flow a heat transfer fluid through the plurality of plates.