| William Hunter Jr. | |
| Order: | 1st |
| Office: | United States Second Assistant Secretary of State |
| Term Start: | July 27, 1866 |
| Term End: | July 22, 1886 |
| President: | Andrew Johnson Ulysses S. Grant Rutherford B. Hayes James Garfield Chester A. Arthur Grover Cleveland |
| Predecessor: | Position established |
| Successor: | Alvey A. Adee |
| Office1: | United States Secretary of State |
| Status1: | Ad interim |
| Term Start1: | December 15, 1860 |
| Term End1: | December 16, 1860 |
| Term Start2: | March 4, 1853 |
| Term End2: | March 7, 1853 |
| President1: | James Buchanan |
| Predecessor1: | Edward Everett |
| Successor1: | William L. Marcy |
| President2: | Franklin Pierce |
| Predecessor2: | Lewis Cass |
| Successor2: | Jeremiah S. Black |
| Order3: | 2nd |
| Office3: | United States Assistant Secretary of State |
| Term Start3: | May 9, 1855 |
| Term End3: | October 31, 1855 |
| President3: | Franklin Pierce |
| Predecessor3: | Ambrose Dudley Mann |
| Successor3: | John Addison Thomas |
| Order4: | 20th |
| Office4: | Chief Clerk of the Department of State |
| Term Start4: | May 17, 1852 |
| Term End4: | May 7, 1855 |
| President4: | Millard Fillmore Franklin Pierce |
| Predecessor4: | William S. Derrick |
| Successor4: | Ambrose Dudley Mann (as Assistant Secretary of State in 1853) |
| Birth Name: | William Hunter, Jr. |
| Profession: | Diplomat |
William Hunter Jr. (November 8, 1805 – July 22, 1886)[1] was a politician and diplomat from Rhode Island. He was a confidential clerk to Secretary of State John Clayton in the United States Department of State from 1849 to 1850, serving with George P. Fisher. He had served as acting Secretary of State on three occasions, once in 1853, again in 1860, and to temporarily substitute for Secretary William H. Seward[2] after his injury in a carriage accident and subsequent wounding in an attack concurrent with the assassination of Abraham Lincoln. He also served as Chief Clerk of the State Department from 1852 to 1855, Assistant Secretary of State in 1855 and Second Assistant Secretary of State from 1866 until his death in 1886.