Diethelm (born 22 October 1957) is a Swiss businessman.
Currently, he serves as Group General Counsel of UBS Group AG, holding this position since 2014.
Prior to that, he held the same position at UBS AG since September 2008, when Diethelm was initially appointed as a member of the Group Executive Board of UBS.
Additionally, he served as an Executive Board member of UBS Business Solutions AG from 2015 to 2016.