The present invention relates to a device for aligning an X-ray grating to an X-ray radiation source, the device (10) comprising at least two flat X-ray grating segments (11-19); at least one alignment unit (31-39) for aligning one of the at least two flat X-ray grating segments; wherein the at least two flat X-ray grating segments (11-19) are arranged in juxtaposition and are forming an X-ray grating (20); wherein the at least two flat X-ray grating segments (11-19) each comprise a grating surface (41-49) for X-ray radiation, each grating surface (41-49) comprising a geometrical center; wherein normals (21-29) to each of the grating surfaces (41-49) define a common plane (73), wherein the normals (21-29) intersect the geometrical center of the grating surface (41-49); wherein at least a first of the at least two flat X-ray grating segments (11-19) is rotatable around an axis (131-139) that is perpendicular to the common plane (73); and wherein the first of the at least two flat X-ray grating segments (11-19) that is rotatable around the axis (131-139) is connected to a first of the at least one alignment unit (31-39). The invention provides a device (10) and a method (100) which provide an improved X-ray grating (20).