Carl Henry Brans (/brænz/; born December 13, 1935) is an American mathematical physicist best known for his research into the theoretical underpinnings of gravitation elucidated in his most widely publicized work, the Brans–Dicke theory.

A Texan, born in Dallas, Carl Brans spent his academic career in neighboring Louisiana, graduating in 1957 from Loyola University New Orleans.

Having obtained his Ph.D. from Princeton University in 1961, he returned to Loyola in 1960 and later became the J.C. Carter Distinguished Professor of Theoretical Physics.

A number of very accurate measurements made in the late 1970s has indicated that JBD fares no better than the simpler standard Einstein General Relativity, in the solar system context.

However, developments in string theory and in inflationary cosmology have renewed interest in scalar field modifications of standard general relativity, although not in the original JBD form.