Klaus Welle is a German politician who served as Secretary General of the European Parliament between 15 March 2009 to 31 December 2022. He was previously Head of the Office of the President of the European Parliament, Hans-Gert Poettering MEP, from January 2007. He succeeded Harald Rømer, a Danish career civil servant, who had reached retirement age. Welle is also an advisor to the Yale University-based transatlantic think tank, European Horizons.