Adrien Loir (December 15, 1862 – 1941) was a French bacteriologist born in Lyon. He was a nephew of Louis Pasteur, and for much of his career was associated with the Pasteur Institute. From 1882 to 1888 Loir was an assistant in Pasteur's laboratory in Paris, where he performed research of swine fever. In 1886, he installed the first anti-rabies clinic in Saint Petersburg. Between 1888 and 1893 he made two journeys to Australia to conduct research of anthrax and pleropneumonia. While there, he investigated the use of chicken cholera bacillus in an attempt to eradicate the country's rabbit infestation.