A mounting device for mounting on a substrate a plate or board-like lighting source may include a frame member for surrounding the plate or board-like lighting source, anchoring formations for anchoring the frame member onto the substrate while permitting movement of the frame member towards and away from the substrate, elastic means for elastically urging the frame member towards the substrate, and one or more locking members mounted on the frame member and radially displaceable with respect to the frame member between: a radially outward position, in which the plate or board-like lighting source can be inserted into the frame member and positioned between the frame member and the substrate, and a radially inward position, in which the locking member(s) abuts/abut against the plate or board-like lighting source located between the frame member and the substrate, elastically urging the plate or board-like lighting source towards the substrate.