| Honorific-Prefix: | The Hon. |
| Pierre Baillargeon | |
| Office: | Senator for Stadacona, Quebec |
| Appointed: | Alexander Mackenzie |
| Predecessor: | Pierre-Joseph-Olivier Chauveau |
| Successor: | Auguste Charles Philippe Robert Landry |
| Term Start: | 1874 |
| Term End: | 1891 |
| Birth Date: | 8 November 1812 |
| Birth Place: | Île-aux-Grues, Lower Canada |
| Party: | Liberal |
Pierre Baillargeon (November 8, 1812 - December 15, 1891) was a physician and political figure in Quebec. He sat for Stadacona division in the Senate of Canada from 1874 to 1891.
He was born in Île-aux-Grues, Lower Canada, the son of François Baillargeon and Marie-Louise Langlois dit Saint-Jean, and was educated at the Collège de Nicolet. Baillargeon received an MD from Harvard University. He was a member of the Boston Medical Society and a visiting physician at the Quebec General Hospital in Quebec City. In 1842,[1] he married Geneviève, the daughter of Joseph Painchaud.[2] Baillargeon died in office at the age of 79.
His brother Charles-François Baillargeon was archbishop of Quebec.