Diamond cutting is the art, skill and, increasingly, science of changing a diamond from a rough stone into a faceted gem. Cutting diamond requires specialized knowledge, tools, equipment, and techniques because of its extreme difficulty.

The first guild of diamond cutters and polishers (diamantaire) was formed in 1375 in Nuremberg, Germany, and led to the development of various types of 'Cut'. This has two meanings in relation to diamonds. The first is the shape: square, oval, and so on. The second relates to the specific quality of cut within the shape, and the quality and price will vary greatly based on the cut quality. Since diamonds are very hard to cut, special diamond-bladed edges are used to cut them. The first major development in diamond cutting came with the "Point Cut" during the latter half of the 14th century: the Point Cut follows the natural shape of an octahedral raw diamond crystal, eliminating some waste in the cutting process.

Diamond cutting, as well as overall processing, is concentrated in a few cities around the world: while 80% of rough diamonds are handled in Antwerp,Belgium, more than 50% of processed diamonds also pass through there. 92% of diamond pieces are cut in Surat, Gujarat state in India. The other important diamond centers are Tel Aviv and New York city.