List of The New York Times number-one books of 1940

This is a list of books that topped The New York Times best-seller list in 1940. When the list began in 1931 through 1941 it only reflected sales in the New York City area.

Fiction
The following list ranks the number-one best-selling fiction books.

The two most popular books that year were How Green Was My Valley, by Richard Llewellyn, which held on top of the list for 13 weeks, and Stars on the Sea by F. Van Wyck Mason, which was on top of the list for 10 weeks.

Nonfiction
The following list ranks the number-one best-selling nonfiction books.