Sweet Adelines International is a worldwide organization of women singers, established in 1945, committed to advancing the musical art form of barbershop harmony through education and performances.

[citation needed] In 2012, Sweet Adelines International claimed a membership of 24,000 women,[6] all singing in English, includes choruses in most of the fifty United States as well as in Australia, Canada, England, Finland, Germany, Ireland, Japan, New Zealand, Scotland, Sweden, Wales and the Netherlands.

This is followed by five regions allocated to Canada, one each to Australia and New Zealand, one each to Great Britain, Ireland and the Netherlands, and Finland and Sweden.

Sweet Adelines International set the Guinness World Record for Largest Singing Lesson on October 24, 2009, at 7:30 p.m.

The record-setting event coincided with the 63rd annual International Convention and Competition held at the Sommet Center in Nashville, Tennessee.

[9] Music professional and past Sweet Adelines International Quartet Champion Peggy Gram led the lesson by demonstrating inspiring techniques for integrating the voice into the art form.

The venue was filled with sound as 6,651 singers practiced the demonstrated techniques and sang simultaneously for the duration of the 10-minute lesson.