"The Trolley Song" is a song written by Hugh Martin and Ralph Blane and made famous by Judy Garland in the 1944 film Meet Me in St. Louis. The song was inspired by a picture of a trolleycar in a children's picture book.

Judy Garland and chorus perform "The Trolley Song" in the Meet Me in St. Louis

Blane and Martin were nominated for the Academy Award for Best Original Song at the 1945 Academy Awards, for "The Trolley Song" but lost to "Swinging on a Star" from Going My Way. "The Trolley Song" was ranked #26 by the American Film Institute in 2004 on the 100 Years... 100 Songs list. The song as conducted by Georgie Stoll for Meet Me in St. Louis has a very complex, evocative arrangement by Conrad Salinger featuring harmonized choruses, wordless vocals, and short highlights or flourishes from a wide range of orchestral instruments.

Frank Sinatra later recorded the song; as well as Sarah Vaughan.

Rufus Wainright kicked off his 2007 re-creation of Garland's legendary 1961 Carnegie Hall concert with a rendition of the song. The performance is featured on the DVD Rufus! Rufus! Rufus! Does Judy! Judy! Judy!: Live From the London Palladium.

A version of the song appears on João Gilberto's João Gilberto en Mexico

Five versions of the song charted in 1944-45. Garland's single and a version by Vaughn Monroe both peaked at number four, but the biggest hit version was by The Pied Pipers, which hit number two on Billboard's Best Sellers in Stores chart the week of December 16, 1944.