Juan Bautista Ambrosetti (August 22, 1865 – May 28, 1917) was an Argentine archaeologist, ethnographer and naturalist who helped pioneer anthropology in his country.
Ambrosetti was born in Gualeguay, Entre Ríos Province, in 1865. He enrolled at the University of Buenos Aires, where he was mentored by the prominent local naturalist, Dr. Florentino Ameghino. At age twenty, he joined an expedition of naturalists into then-remote and largely uncharted Chaco Province, publishing his observations in Buenos Aires by a pseudonym, Tomás Bathata.
Following graduation, he was appointed Director of Zoology at the Provincial Museum of Entre Ríos, in Paraná. Ambrosetti's reputation in his field was first earned with his publication of studies on the ethnomusicology and cemeteries of the native peoples of Misiones Province, in 1893-95, and with The Megaliths of Tafí del Valle (1896). He collaborated with a number of local scientific institutions in subsequent years, including work for his alma mater's School of Philosophy and Letters, the Argentine Geographic Institute, the La Plata Museum, the Bernardino Rivadavia Natural Sciences Museum (where he collaborated with Ameghino), and the Buenos Aires Zoo (likewise led by a former teacher, Eduardo Ladislao Holmberg).
Ambrosetti contributed to a number of peer-reviewed journals, including the National Academy of Sciences Bulletin (Córdoba) and the National Agricultural Bulletin, contributing over 70 articles in all. He joined the Argentine Scientific Society and the Western Hemisphere Historical and Numismatic Association in 1901, representing Argentina at the 1902 Scientific Congress (in New York City), becoming the first Argentine to participate in the event. He was named Professor of Archaeology in 1903, and established the University of Buenos Aires Museum of Ethnography, in 1904. His text, Argentine Archaeology: Bronze in the Calchaquí Region (1904), would remain among the definitive texts on the subject.