"Roly-Poly" is a dance-pop song by South Korean girl group T-ara. It was taken from their second mini album John Travolta Wannabe, released on June 29, 2011. The song was written and produced by Shinsadong Tiger and Choi Gyu Sung, who were also behind the group's hit song "Bo Peep Bo Peep". "Roly-Poly" won three weekly #1 awards on Mnet's M! Countdown and SBS's Inkigayo, and went on to becoming the top grossing and most downloaded song of 2011 with a record $2 million in sales and 4,077,885 downloads.
A remix of the song titled "Roly-Poly in Copacabana" was released on August 2 and was used for the group's follow up promotions.
In 2012, "Roly-Poly" was made into a stage musical starring T-ara's Hyomin, Jiyeon and Soyeon, Kang Min-kyung (Davichi), Jang Hye-jin (I Am a Singer), veteran musical actress Park Hae-mi, Han Ji-sub, Kim Jae-hee and Yoon Young-joon.
The song was re-released in Japanese on February 29, 2012, as the group's third single.
Stereogum ranked the music video of the song No. 12 on its list of 20 Best K-pop videos. It was named the fourth best K-pop song by Edge Media.
On the Gaon Digital Chart dated June 26, 2011, "Roly-Poly" debuted at number three, before descending to number eight the week after. On its' third week it bounced back to number two, the song's peak on the chart. "Roly-Poly" managed to hold at the runner-up slot for two more weeks (stuck behind three different songs nonetheless), before descending down the chart. Despite never topping the weekly or monthly chart and having a little less than half a year to chart, "Roly-Poly" managed to become the best-performing song of the year on the Gaon Digital Chart.