Daniel Calhoun Roper (April 1 1867 – 1943) was a U.S. administrator. He served as the Secretary of Commerce between 1933 and 1938 and as Ambassador to Canada in 1939.
| Preceded by: Roy D. Chapin |
Secretary of Commerce | Succeeded by: Harry L. Hopkins |
| Preceded by: Norman Armour |
Ambassadors to Canada | Succeeded by: James H.R. Cromwell |