The Multiple Light Source dataset (MLS) is a collection of 24 multiple object scenes each recorded under 18 multiple light source illumination scenarios. The illuminants are varying in dominant spectral colours, intensity and distance from the scene. The dataset can be used for the evaluation of computational colour constancy algorithms. Along with the images of the scenes the spectral characteristics of the camera, light sources and the objects are also provided, and each image includes pixel-by-pixel ground truth annotation of uniformly coloured object surfaces thus making this useful for benchmarking colour-based image segmentation algorithms.