Theodore Frank Appleby (October 10, 1864 – December 15, 1924) was an American Republican Party politician who represented New Jersey's 3rd congressional district for one term in the United States House of Representatives from 1921 to 1923.

Born on October 10, 1864, in Old Bridge, New Jersey, Appleby graduated from Fort Edwards Collegiate Institute in 1885.

During this election Appleby was endorsed by the Ku Klux Klan.

[2] He died on December 15, 1924, in Baltimore, Maryland before he could take his seat, and was replaced by his son, Stewart Appleby.

[3] He was buried in Chestnut Hill Cemetery near Old Bridge in East Brunswick, New Jersey.