| Robert Irwin | |
| Birth Date: | January 17, 1865 |
| Birth Place: | Shelburne, Nova Scotia |
| Death Place: | Shelburne, Nova Scotia |
| Residence: | Shelburne, Nova Scotia |
| Office1: | MLA for Shelburne County |
| Term Start1: | June 20, 1906 |
| Term End1: | June 25, 1925 |
| Predecessor1: | Thomas Johnston George A. Cox Thomas Robertson Moses H. Nickerson |
| Successor1: | Ernest Reginald Nickerson |
| Alongside1: | Moses H. Nickerson, Smith Nickerson, Maurice Nickerson, Frank E. Smith, Ernest Howard Armstrong |
| Office2: | Speaker of the Nova Scotia House of Assembly |
| Term Start2: | January 31, 1917 |
| Term End2: | June 25, 1925 |
| Predecessor2: | James F. Ellis |
| Successor2: | Albert Parsons |
| Office3: | 17th Lieutenant Governor of Nova Scotia |
| Term Start3: | April 7, 1937 |
| Term End3: | May 31, 1940 |
| Predecessor3: | Walter Harold Covert |
| Successor3: | Frederick Francis Mathers |
| Monarch3: | George VI |
| Governor General3: | The Lord Tweedsmuir The Earl of Athlone |
| Premier3: | Angus Lewis Macdonald |
| Party: | Liberal |
| Occupation: | salesman |
Robert Irwin (January 17, 1865 - May 16, 1941) was a merchant and political figure in Nova Scotia, Canada, and father of Robert Grandy and Prescott St. Clair. He represented Shelburne County in the Nova Scotia House of Assembly from 1906 to 1925 as a Liberal member. Irwin was the 17th Lieutenant Governor of Nova Scotia from 1937 to 1940.
He was born in Shelburne, Nova Scotia, the son of Robert Gore Irwin and Isabel Archer, and was educated there. Irwin worked for fifteen years as a travelling salesman before establishing a lumber and dry goods business at Shelburne. In 1894, he married Mary Prescott McGill. Irwin was speaker for the provincial assembly from 1917 to 1925. He died in Shelburne. His brother Harry Irwin was Hawaii Attorney General and a judge in Hawaii. His brother Fred was a physician and surgeon in Hawaii. They also had a brother named Archer.