"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 Let There Be Rock, released in June the same year.
It was also released as a single, with a B-side of "Dog Eat Dog", in 1978.
The song's lyrics are based on Bon Scott's actual sexual experiences with an obese woman, whose first name was Rosie. There is an ongoing search for the real Rosie, although she has yet to be found.
Some believe the title is a reference to the Led Zeppelin classic "Whole Lotta Love", but it is more likely just a variation of the idiomatic English phrase "a whole lot of [something]": hence the chorus lyric, "you're a whole lotta woman".
The song's main riff was also featured on an earlier recording with different lyrics, titled "Dirty Eyes", which saw official release on Volts, part of the Bonfire box set. "Dirty Eyes" features a different chord progression in the chorus, as well as a slower tempo than "Rosie".