Louis Henri Vaquez (27 August 1860 – 15 April 1936) was a French internist born in Paris. He is known for his work in the field of hematology and his research of heart disease. In 1890 he earned his medical doctorate, and in 1895 became médecin des hôpitaux in Paris. In 1898 he was promoted to professeur agrégé, and in 1918 was appointed professor of clinical medicine and elected a member of the Academy of Medicine. Cardiologist Pierre Potain (1825–1901) was an important influence in his medical career.