| Honorific-Prefix: | Hon. |
| Robert Nelson Chamberlain | |
| Office: | 2nd Chief Justice of the New Hampshire Superior Court |
| Term Start: | January 23, 1917 |
| Term End: | September 20, 1917 |
| Succeeded: | John Kivel |
| Term Start2: | 1904 |
| Term End2: | 1917 |
| Succeeded2: | John Eliot Allen |
| Term Start3: | 1893 |
| Term End3: | 1895 |
| Succeeded3: | Stephen S. Jewett |
| Birth Date: | July 24, 1856 |
| Death Date: | September 19, 1917 |
| Party: | Republican Party |
Robert Nelson Chamberlain (July 24, 1856 – September 20, 1917) (sometimes spelled Chamberlin[1]) was an American lawyer and Republican politician who served as Speaker of the New Hampshire House of Representatives, and as an Associate Justice and later as the second Chief Justice of the New Hampshire Superior Court.
Chamberlin was born on July 24, 1856, in Bangor, New York, but moved to Berlin, New Hampshire, when he was a child. As an adult, Chamberlain became interested in town and state affairs and became a lawyer, the first lawyer in said town.
Chamberlin became involved with politics, and from 1893 to 1895, he served as the Speaker of the New Hampshire House of Representatives. In 1904, he was appointed as an associate justice of the New Hampshire Superior Court. Chamberlain was appointed as Chief Justice of the New Hampshire Superior Court in 1917 to replace Robert G. Pike who had died.
Chamberlain died in Boston, Massachusetts, on September 19, 1917.