The Latimer–MacDuffee theorem is a theorem in abstract algebra, a branch of mathematics. It is named after Claiborne Latimer and Cyrus Colton MacDuffee, who published it in 1933. Significant contributions to its theory were made later by Olga Taussky-Todd.
Let be a monic, irreducible polynomial of degree . The Latimer–MacDuffee theorem gives a one-to-one correspondence between -similarity classes of matrices with characteristic polynomial and the ideal classes in the order