| John Wesley Brien | |
| Smallimage: | John Wesley Brien.jpg |
| Constituency Mp: | Essex South |
| Parliament: | Canadian |
| Predecessor: | Alfred Henry Clarke |
| Successor: | George Perry Graham |
| Term Start: | 1917 |
| Term End: | 1921 |
| Birth Date: | November 24, 1864 |
| Birth Place: | Victoria County, Canada West |
| Death Date: | January 11, 1949 |
| Party: | Unionist Party |
| Occupation: | physician |
John Wesley Brien (November 24, 1864 - January 11, 1949) was a Canadian politician and physician. He was elected to the House of Commons of Canada in the 1917 election as a Member of the Unionist Party to represent the riding of Essex South. Prior to his federal political career, he had just served a year in the Canadian Expeditionary Force as a medical officer before being forced to return home due to injury. He also served as a captain in the British Canadian Recruiting Mission in Chicago, Illinois, United States of America.
Brien was born in Victoria County, Canada West. His cousin, James Brien, was also a Member of the House of Commons of Canada.