"Whole Lotta Rosie" is a song by Australian hard rock band AC/DC. It is the eighth and final track on the band's fourth Australian album, Let There Be Rock, released in Australia in March 1977, and was written by Angus Young, Malcolm Young, and Bon Scott. It is also the eighth and final track on the international version of the album, released in June the same year.

It was also released as a single in 1978, with a live version of the Let There Be Rock album track "Dog Eat Dog" as the B-side, which had been recorded in concert in Glasgow on 30 April 1978.

The song is about an obese Tasmanian woman, Rosie, with whom the singer (Bon Scott) had a one-night stand at the Freeway Gardens Motel in North Melbourne. In addition to pointing out the woman's size, the singer finds her to be one of the most talented lovers he's ever experienced.

The song's first verse reveals Rosie's substantial physical measurements (42"-39"-56"), and that she weighs nineteen stone (266 pounds/approximately 120 kilograms). On the Live from the Atlantic Studios disc, however, Scott describes the titular woman as "... a Tasmanian devil ... weighs 305 pounds (138kg)...," a measurement that differs from the "19 stone" lyric (305 lb being 21 st 11 lb).

In 1998, speaking to Vox magazine, Angus Young remembered:

We'd been in Tasmania and after the show [Bon Scott] said he was going to check out a few clubs. He said he'd got about 100 yards down the street when he heard this yell: 'Hey! Bon!' He looked around and saw this leg and thought: 'Oh well!' From what he said, there was this Rosie woman and a friend of hers. They were plying him with drinks and Rosie said to him: 'This month I've slept with 28 famous people,' and Bon went: 'Oh yeah?!' Anyway, in the morning he said he woke up pinned against the wall, he said he opened one eye and saw her lean over to her friend and whisper: '29!' There's very few people who'll go out and write a song about a big fat lady, but Bon said it was worthy.

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