Joseph Hardcastle

Joseph Hardcastle may refer to:
 * Joseph Hardcastle (1752–1819), English merchant and a founder of The Missionary Society
 * Joseph Hardcastle (politician), British Liberal Party MP
 * Joseph Alfred Hardcastle, FRAS (1868–1917), grandson of Joseph Hardcastle (politician) and Sir John Herschel appointed Director of Armagh Observatory just before his death
 * Joseph Hardcastle (accountant) (died 1906), American Certified Public Accountant