An X-ray optics assembly for an X-ray diffractometer is provided, comprising a multilayer mirror, in particular a Goebel mirror, and a switching system with which beam paths for an X-ray beam are selectable. The X-ray optics assembly includes a monochromator, in particular a channel-cut crystal, and three beam paths for the X-ray beam are selectable using the switching system. A first beam path in a first position of the switching system leads past the multilayer mirror and leads past the monochromator, a second beam path in a second position of the switching system contains the multilayer mirror and leads past the monochromator, and a third beam path in a third position of the switching system contains the multilayer mirror and contains the monochromator. The invention provides an X-ray optics assembly and an X-ray diffractometer which may be used even more universally for various measurement geometries in a simple manner.