| Reuben Eldridge Truax | |
| Riding1: | Bruce South |
| Parliament1: | Canadian |
| Term Start1: | 1913 |
| Term End1: | 1921 |
| Predecessor1: | James J. Donnelly |
| Successor1: | John Walter Findlay |
| Office2: | Ontario MPP |
| Term Start2: | 1908 |
| Term End2: | 1911 |
| Predecessor2: | Robert Edwin Clapp |
| Successor2: | John Anderson |
| Term Start3: | 1894 |
| Term End3: | 1904 |
| Predecessor3: | Hamilton Parke O'Connor |
| Successor3: | Robert Edwin Clapp |
| Constituency3: | Bruce South |
| Riding4: | Bruce East |
| Parliament4: | Canadian |
| Term Start4: | 1891 |
| Term End4: | 1892 |
| Predecessor4: | Henry Cargill |
| Successor4: | Henry Cargill |
| Party: | Liberal |
| Birth Date: | 11 October 1847 |
| Birth Place: | Montreal, Canada East |
| Occupation: | Businessman |
Reuben Eldridge Truax (October 11, 1847 - April 3, 1935) was an Ontario businessman and political figure. He represented Bruce South in the Legislative Assembly of Ontario from 1894 to 1904 and from 1908 to 1911 and Bruce East in 1891 and Bruce South from 1913 to 1921 in the House of Commons of Canada as a Liberal member. Truax served four years as reeve and was mayor of Walkerton, Ontario in 1888 and 1889.
He was born in Montreal, Canada East in 1847 and educated in Walkerton, Ontario. In 1870, he married Jessie Porteous. He owned a sawmill, planing mill and sash and door factory. He was first elected to the House of Commons in 1891 but that election was declared invalid and Henry Cargill was elected by acclamation in the by-election which followed. Truax was an unsuccessful candidate for the federal seat in Bruce South in 1911 and 1921.