Abstract: A fastening system is used to attach architectural panels to a building structure in which three panel brackets are attached along the bottom and side edges of the panel. These panel brackets each have a front face adapted to extend along the rear surface of the panel adjacent to one of the panel's peripheral edges; a panel-gripping flange extending from the front face suitable for insertion into a groove extending along the peripheral edge of the panel; and a channel with an opening extending parallel to the peripheral edge of the panel. A top panel bracket is also attached along the top edge of the panel, which has a front face and a panel-gripping flange as before, and which further has a support member to secure the top panel bracket to the building structure; and a vertical flange extending upward at a predetermined spacing from the building structure.