List of Number-one Singles of 1940 (U.S.)

This is a list of number-one songs in the United States during the year 1940 according to Billboard magazine.

A feature of the July 27, 1940, issue, the 10-position "National List of Best Selling Retail Records" began Billboard's tracking of music popularity.

Prior to July 27, 1940, Billboard had featured lists of national "Sheet Music Best Sellers"; "Records Most Popular on Music Machines" (compiled from national reports from phonograph operators); and "Songs With the Most Radio Plugs" based on a few of New York radio stations.

The "National List of Best Selling Retail Records," however, was the first to poll retailers nationwide on record sales.

The new chart was termed a "trade service feature" based on the "10 best selling records of the past week" at a selection of national retailers from New York to Los Angeles

Tommy Dorsey scored first for the inaugural retail list with the song "I'll Never Smile Again", which, featuring vocals by Frank Sinatra and the vocal group the Pied Pipers, would total 12 weeks as number 1.

Shown is a list of songs that scored best on the National List of Best Selling Retail Records chart.