Ace of Angels is the first studio album and major Japanese release by South Korean girl group AOA.

To promote the album, AOA embarked on their first Japan concert tour, Angels World 2015 ~Oh Boy Academy~, in December 2015.

[5] A dance version was officially released on February 25, 2015 on AOA's Vevo channel.

The physical single included the Japanese versions of "Confused" and "Joa Yo!

", which were previously available on the fourth Korean single album Red Motion (2013) and the first EP Short Hair (2014), respectively.