Ernst Kraft Wilhelm Nußelt (Nusselt in English; November 25, 1882, in Nuremberg – September 1, 1957, in Munich) was a German engineer.
Nusselt studied mechanical engineering at Technische Universität München, where he got his doctorate in 1907.
After teaching and working in Switzerland and Germany between 1917 and 1925, he was appointed to the chair of theoretical mechanics in Munich.
He held that position until 1952, being succeeded in the job by another important figure in the field of heat transfer, Ernst Schmidt.
The Nusselt number used in Fluid Mechanics and Heat Transfer is named in his honour.