A low-profile lighting module with light-emitting diodes (LEDs) has a water-tight seal between a molded-plastic cover and a printed circuit board (PCB). A substrate with the LEDs fits up into an indentation in the lower surface of the PCB. Landing pads on the top of the substrate attach to contact pads in the indentation that are extensions of a conductor of the PCB which is electrically coupled through the landing pads to the LEDs. A lens with a curved optical portion surrounded by a flat lip fits into another indentation on the upper surface of the PCB. A highly reflective sheet is disposed between the planar lower surface of the lens and bottom of the indentation in the upper surface. A double-sided adhesive sheet is disposed under the inside surface of the molded-plastic cover and over both the upper surface of the PCB and the flat lip of the lens.