Louis Havet should not be confused with Louis Hayet.
| Birth Date: | 6 January 1849 |
| Birth Place: | Paris, French Second Republic |
| Death Place: | Paris, French Third Republic |
| Known For: | Thurneysen–Havet's law |
| Workplaces: | Collège de France |
| Fields: | linguistics, classical languages |
Pierre Antoine Louis Havet (in French avɛ/; 6 January 1849 – 26 January 1925) was a French Latinist and Hellenist, an expert on classical Greek and Latin poetry. He was the son of Ernest Havet.
He was professor at Collège de France, where between 1885 and 1925 he was chairman of the department of Latin philology. Beginning in 1893, he was a member of the Académie des Inscriptions et Belles-Lettres. In 1917, he became the first vice-president of the Association Guillaume Budé.
He was a member of the central committee of the Human Rights League, which defended Alfred Dreyfus in the Dreyfus affair.