The assembly includes an archery bow with an arrow shelf and sidewall defining an arrow window and an arrow rest disposed in and behind the window and supporting an arrow in the window for shooting from the bow. The rest has a mounting bracket which includes a mounting arm rigidly secured at a plurality of points to the bow sidewall on the side opposite the window. The arm extends horizontally rearwardly to a point behind the bow. The arm's rear end bears a groove in which a transverse crossbar is slideably received. The crossbar has a long slot in it and a scale around the slot. A screw clamps the arm and bar together through the groove and slot. The screw can, if desired, be geared to the slot, so that rotation of the screw moves the crossbar transversely. The bar bears a rotatable post behind the window. The rear end of an arrow support is releasably locked in the post and the arrow support is seated in a horizontal slot in the post and extends forward thereof, ending in a front curved portion which holds the arrow shaft and prevents arrow roll off. The post has a return spring or magnet secured to it, as well as an adjustable collar and screw bearing against a stop pin to limit its rotation. The rest is fully adjustable to fit bows of various sizes and types.