An illuminated sign having front, back and side surfaces. A plurality of first cavities are formed into the back surface of the sign. A plurality of light emitting modules are disposed in the plurality of first cavities. The modules each include a light emitting diode having an emission axis and for producing at least some light output generally parallel to the emission axis, an optical device disposed adjacent the light source having a reflective surface for reflecting the light output in directions that are generally perpendicular to the emission axis, and a guide element disposed adjacent the optical device for coupling the reflected light output into the interior of the sign. The guide element includes a second cavity formed therein in which the optical device is disposed. The front surface is illuminated by the coupled light output from the light emitting modules by reflection and/or diffusion inside the sign.