Peter Gruss (born 28 June 1949 in Alsfeld, Hesse) is a German developmental biologist, and the former president of the Max-Planck-Gesellschaft (having been elected for the term from 2002 to 2008 and reelected for the current term 2008-2014).Gruss's research has generally covered the topic of control mechanisms in the development of mammals, especially in the development of the nervous system. He has been able to produce insulin using stem cells.