A driver monitoring system (10) for a motor vehicle comprises an illumination apparatus (20) adapted to illuminate the driver's face (21) with optical radiation (22), an imaging device (12) directed to the driver's face (21), and a processing device (14) adapted to evaluate driver attentiveness through image processing of images captured by said imaging device (12). The illumination apparatus (20) is adapted to generate polarized illumination radiation (22), and the driver monitoring system (10) comprises an imaging side polarization filter (29) arranged in the path of reflected radiation from the driver's face (21) to the imaging device (12).
