Abstract: A holder for polygonal cross-section cuvettes is provided. The holder comprises a handle having and lying on an axis, and a holding plate connected to and extending radially from the handle. The holding plate is formed with a plurality of apertures each having a periphery. The periphery is formed with a plurality of notches corresponding in number and arrangement to the longitudinally directed edges of a polygonal-section cuvette. Inwardly concave portions are formed between the notches and connect the same in such a manner that a cuvette inserted in an aperture is held only at its longitudinally directed edges which engage only the notches. A supporting plate is also provided. This support plate is connected to the handle and spaced from and generally parallel to the holding plate in such a manner that a cuvette inserted in an aperture stands on the support plate.