Theodore Runyon (October 29, 1822 – January 27, 1896) was a United States politician, diplomat, and American Civil War brigadier general in the New Jersey Militia, serving with the Union Army at the Battle of First Bull Run. Runyon was a lawyer before the Civil War and mayor of Newark, New Jersey, a major general in command of the New Jersey National Guard until 1873, first president of the Manufacturers' National Bank of Newark, chancellor of New Jersey for 14 years and, between 1893 and 1896, envoy and later ambassador to Germany.