The Fleischmann's Yeast Hour (aka The Rudy Vallée Show, aka The Fleischmann Yeast Hour, aka The Fleischmann Hour) was a pioneering musical variety radio program broadcast on NBC from 1929 to 1936, when it became The Royal Gelatin Hour, continuing until 1939. This program was sponsored by Fleischmann’s Yeast, a popular brand of yeast.

The person responsible for this major step ahead in broadcasting was NBC executive Bertha Brainard, who became head of programming for NBC in 1928. She began pushing for singer-bandleader Rudy Vallée to host a variety series by explaining that only a woman could understand the appeal of Vallée's voice.

Beginning October 24, 1929, the show quickly became a top-rated program, second only to Amos 'n' Andy. Host Vallée appeared along with regulars Ole Olsen and Chic Johnson (1932), followed by Tom Howard and George Shelton (1935). On this show, the American listening audience heard many future stars for the first time, as it introduced such talents as Milton Berle, Burns and Allen, Alice Faye, the Mills Brothers and Kate Smith. Gloria Swanson made her radio debut. Other guests included Ray Bolger, Fannie Brice, Ilka Chase, Helen Hayes and Bert Lahr.

In 1937, at Vallée's instance, Louis Armstrong hosted the show during Vallée's summer vacation. This made Armstrong the first Black American to host a national network program.

As The Royal Gelatin Hour, the program came to an end on September 28. 1939. Both products were made by Standard Brands, so the sponsorship remained the same. Vallée continued on NBC with sponsors Sealtest, Kraft Foods, Drene Shampoo and Philip Morris.