"I'm Sorry" is a 1960 hit song by 15-year-old American singer Brenda Lee. It peaked at No. 1 on the Billboard Hot 100 singles chart in July 1960. AllMusic guide wrote that it is the pop star's "definitive song", and one of the "finest teen pop songs of its era". It was written by Dub Allbritten and Ronnie Self. On the UK Singles Chart, the song peaked at No.12.

According to the Billboard Book of Number One Hits by Fred Bronson, Brenda Lee recorded the song early in 1960, but her label, Decca Records, held it from release for several months out of concern that a 15-year-old girl was not mature enough to sing about unrequited love. When the song finally was released, it was considered to be the flip side of the more uptempo "That's All You Gotta Do". Although "That's All You Gotta Do" was a chart success in its own right, reaching No. 6 on the Hot 100, it was "I'm Sorry" that became the smash hit and the standard. On other charts, "I'm Sorry" peaked at number four on the R&B chart and "That's All You Gotta Do" peaked at number nineteen on the R&B charts.

"I'm Sorry" was released as the A-side (with "That's All You Gotta Do" as the B-side) when the single was released in the U.K. in July 1960. "I'm Sorry" was not one of Lee's more successful singles in the U.K., where Lee's previous single, "Sweet Nothin's", and several later releases (notably "Speak to Me Pretty", "All Alone Am I" and "As Usual") were substantially bigger hits.

Although "I'm Sorry" was never released to country radio in the United States as a single, it would in time become accepted by American country fans as a standard of the genre. The song — a fixture on many "country oldies" programs — was an early example of the new "Nashville sound", a style that emphasized a stringed-instrumental sound and background vocals.

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