Hans Ulrich Lehmann studied violoncello at the Biel Conservatory in his hometown and music theory with Paul Müller-Zürich at the Zurich University of the Arts.
From 1960 to 1963 he attended master classes in composition with Pierre Boulez and Karlheinz Stockhausen at the City of Basel Music Academy.
He also studied musicology with Kurt von Fischer at the University of Zurich.
From 1961 to 1972 he was a lecturer at the City of Basel Music Academy and from 1969 to 1990 lecturer for Neue Musik and music theory at the University of Zurich and from 1990 at the University of Bern.
Among his students were Wolfram Schurig, Manuel Hidalgo, Hwang Long Pan, Stefan Keller, Gérard Zinsstag, Alfred Zimmerlin, Mischa Käser, Thomas Gartmann and Max E. Keller.