An exhaust diffuser for a truck includes a chamber mountable on a truck exhaust stack pipe. The chamber has a cross sectional area much greater than the cross sectional area of the exhaust pipe, and has a dispersing element disposed in the line of exhaust flow to divert exhaust gases laterally into the chamber volume. One or both of the top and front side walls are formed as a mesh or screen to allow the dispersed exhaust gases to flow outward away from the truck cab in a diffused area.
