An apparatus for measuring a wavelength-dependent optical characteristic of an optical system has a light-pattern generation device which generates a pattern of polychromatic light in an object plane. Together with the optical system, a measuring optical unit images the object plane on a spatially resolving light sensor. A dispersive optical element is arranged in a light path between the optical system and the light sensor in such a way that a plurality of images of the pattern with different wavelengths are generated simultaneously on the light sensor. The evaluation device determines the wavelength-dependent characteristic of the optical system from the plurality of images on the light sensor.