White-Jacket; or, The World in a Man-of-War is the fifth book by American writer Herman Melville, first published in London in 1850. The book is based on the author's fourteen months' service in the United States Navy, aboard the frigate USS Neversink (actually ).

Although early biographers of Melville assumed the account was reliably autobiographical, scholars have shown that much in the book was taken and transformed from popular sea books.