The invention relates to a light module (1) for a lighting device for a motor vehicle. The lighting module (1) comprises a light source (3) for emission of electromagnetic radiation, preferably in the form of light which is visible for the human eye, and a reflector (2) for focusing the emitted radiation. At its apex, in the area of its optical axis (8), the reflector (2) has an opening (7) for holding a light-emitting part (5) of the light source (3). A reflector neck (9) is formed on the reflector (2), surrounding at least a part of the holding opening (7), to which reflector neck (9) another part (4, 6) of the light source (3) is attached. In order to reduce the installation space required for lighting devices in a motor vehicle, it is proposed that the reflector (2) has a slot (17), which extends into the holding opening (7), below the holding opening (7), the width of which slot (17) transversely with respect to the optical axis (8) of the reflector (2) is greater than the width of the light-emitting part (5) of the light source (3). The lamp (3) can therefore be replaced more easily, and in less space.