Halfdan Sundt (12 August 1873 – 18 January 1951) was a Norwegian physician and politician.
He was born in Farsund as a son of consul Peter Ingvard Sundt (1841–1917) and his wife Anna Christiane Salvesen.
He was a triplet brother of physician Vigleik Trygve Sundt.
[2][3] In September 1903 in Eidsvoll he married merchant's daughter Rebekka Heitmann.
From 1933 to 1935 he was the president of the Norwegian Medical Association, and from 1937 to 1945 he chaired Nationalforeningen mot tuberkulose.