An illumination system comprises at least one light source (2) and a light-guide (1). A first part of the light-guide (1) is defined by a surface (12) for light emission and a back surface (13), and a second part of the light-guide is defined by a light receiving surface (14) and a light reflecting surface (15). The light source (2) is disposed adjacent or substantially adjacent to the light receiving surface (14), and light from the light source enters the light-guide through the light receiving surface (14), and is reflected by the light reflecting surface (15) into the first part of the light-guide. Light is emitted from the waveguide through the surface (12) for light emission, and may be used to illuminate, for example, a display device placed over the surface (12) for light emission. The light source and the light receiving surface are on the same side of the waveguide as the surface for light emission.