The invention relates to a luminaire that enables the use of more sparsely distributed light sources, having a uniform fixture surface brightness and good color mixing. The luminaire comprises first and second light guide layers (10, 11) optically coupled together by at least one optical coupler (12a, 12b), which allows the passage of light from the first (10) to the second light guide layer (11). The luminaire also comprises a plurality of light sources (16a, 16b), each of which being arranged such that light emitted by the light source (16a, 16b) is coupled into the first light guide layer (10) at an interface surface (17)arranged substantially perpendicularly to a longitudinal axis of the first light guide layer (10). The luminaire further comprises a scattering element (14) adapted to cause light to be emitted from an emitting surface of the second light guide layer (11). By providing two optically coupled light guide layers (10, 11), one for receiving light emitted by the light sources (16a, 16b) and the other for emission, greater opportunity for dispersion and color mixing of the light is provided.