Amos Gager Throop (/ˈtruːp/ TROOP; 1811–1894) was an American businessman and politician in Chicago, Illinois during the 1840s and 1850s.

[1] He was instrumental in securing financing from New York to rebuild the wooden frontier town into a city of brick and mortar.

A fervent adherent to a liberal religion, Throop established a Universalist group in Pasadena in 1886.

He is now best known for founding in 1891 (with a gift of over $100,000) the California Institute of Technology, which is today one of the world's most selective universities.

It is currently a private college preparatory school across the street from Caltech with grades ranging from K-12.