Abstract: A window bracing device which is used to support a window unit within a window opening of a wall of a structure while that window unit is being secured to the structure, with the window bracing device being temporarily attached to the window unit on the interior side of the window unit, then braced against the interior of the wall surrounding the window opening, retaining the window unit in place while a worker secures the window unit to the wall; wherein the window bracing device is comprised of a bracing arm, a first foot, a second foot, a window engagement member, and an attachment component.