Abstract: The instrument mount assembly of the present invention comprises a pair of spaced apart L shaped brackets having a vertical leg and a horizontal flange extending outwardly from a bottom end thereof in a first direction and a hook at a top end thereof sized and configured to securely engage over a body rail of a truck, extending outwardly from the vertical leg in a direction opposite the flange, each flange being adapted to engage an end edge of an isolation plate sized and configured to support a corresponding instrument thereon, the brackets being engaged to one another by at least one cross rail, with the entire assembly being sized and configured to compactly hold the instrument to the body rail of the truck without interfering with any truck structures proximate thereto.