| Pierre Malcom Guay | |
| Constituency Mp: | Lévis |
| Parliament: | Canadian |
| Predecessor: | Isidore-Noël Belleau |
| Successor: | Louis-Jules Demers |
| Term Start: | 1885 |
| Term End: | 1899 |
| Birth Date: | 26 March 1848 |
| Birth Place: | Saint-Romuald d'Etchemin, Canada East |
| Party: | Liberal |
Pierre Malcom Guay (March 26, 1848 - February 19, 1899) was a physician, surgeon and political figure in Quebec. He represented Lévis in the House of Commons of Canada from 1885 to 1899 as a Liberal member.
He was born in Saint-Romuald d'Etchemin, Canada East, the son of François Xavier Guay and Marie Adelaide Côté. Guay was educated at the Séminaire de Quebec and the Université Laval, where he received a M.D. In 1874, he married Marie Louise Antoinette Roy. He served on the town council for St-Romuald d'Etchemin and was mayor from 1886 to 1887. Guay was also a governor of the board of physicians and surgeons for Quebec. He was first elected to the House of Commons in an 1885 by-election held after Isidore-Noël Belleau was unseated following an appeal. Guay died in office at the age of 50.