Bohuslav Brauner (8 May 1855 – 15 February 1935) was a Czech chemist. He worked at the University of Prague, where he investigated the properties of the rare earth elements, especially the determination of their atomic weights. Brauner predicted the existence of the rare earth element promethium ten years before the existence of the gap was confirmed experimentally (although the element was still undiscovered). In the 1880s, when he already had started lecturing in Prague, he still competed internationally in cycling races.