Theodore de Laguna (d. 1930) was an American philosopher who taught for years at Bryn Mawr College and was known as an early feminist.
He was the son of Alexandro Francisco Lopez de Leo de Laguna, a French-U.S. academic who was born in upper Normandy, France, and was of Italian and Jewish ancestry, and Fredericke Bergner, the daughter of refugees from the 1848 revolution in Germany.
His mother died young, and he was raised by an aunt, Frederica.
He received a B.A. and M.A. from the University of California, Berkeley, and a Ph.D. in philosophy from Cornell University.
In 1901 he volunteered as a teacher in the Philippines in the aftermath of the Spanish-American War.
Upon his return he taught at Cornell, where he met and married a Ph.D. student, Grace Mead Andrus. In 1907 Theodore and Grace both began teaching philosophy at Bryn Mawr College.
He died in 1930.
His children included the anthropologist Frederica de Laguna.