A fuel injector heat exchanger assembly is provided, in which the fuel injector assembly includes a body defining an outer surface and an inner surface. The body includes a plurality of walls in concentric arrangement. The plurality of walls defines a plurality of passages including a first passage surrounded by a second passage, and a third passage surrounding the second passage. Each passage is fluidly segregated from one another by the plurality of walls. A first conduit wall is defined through the body from the outer surface. The first conduit wall defines a first conduit in fluid communication with the second passage. The first conduit wall fluidly segregates the first conduit from the third passage. The first conduit is configured to admit a flow of fluid from outside the fuel injector into the second passage.