The invention relates to an illumination device for a motor vehicle, comprising one or more LED units (1) having one or more LEDs and a plate-shaped diffusor (4) having a first and second delimiting surface (401, 402), between which a light-diffusing material having a specified thickness (d) is located. A face of the diffusor (4), which is is provided between the first and second delimiting surfaces (401, 402), forms the light emission surface (403) of the illumination device that is visible to an observer. Furthermore, the LED unit (1) or LED units (1) is/are arranged adjacent to the first delimiting surface (401) and, during operation, emit light toward the first delimiting surface (401), which enters the diffusor (4) via the first delimiting surface (401). According to the invention, the diffusor (4) is designed and arranged such that at least one part of the light of the LED unit (1) or LED units (1) entering via the first delimiting surface (401) is directed in the diffusor (4) to the light outlet surface (4) and emerges there from the illumination device.