Thomas Barbour Lathrop (January 28, 1847 – May 17, 1927) was an American philanthropist and world traveler. He was born in Alexandria, Virginia to Jedediah Hyde Lathrop, a descendant of the Lathrop family of New Hampshire, and Mariana Bryan, of Virginia. His older brother was Bryan Lathrop and younger sister was Florence Lathrop. At the outbreak of the American Civil War, Lathrop's father, an abolitionist, moved the family to Chicago. Lathrop spent two years at a New York City boarding school before being sent to Germany to attend the University of Bonn. Upon his return, he attended Harvard Law School, graduating in 1869. Lathrop was a member of the Barbour family on his mother's side.