Happy Ending is the debut extended play by the South Korean girl group DIA.

This release marked the return of members Heehyun and Chaeyeon, after their hiatus in order to participate on Mnet's survival show, Produce 101.

Members Heehyun and Chaeyeon joined the survival show Produce 101 in 2015 and due to this, they had to temporarily withdraw from the group.

The group filmed their new music video in Jeju Island and will be returning without Seunghee, who left to pursue an acting career after her contract expired on April 30.

[8] The EP also debuted at number 24 on the chart for the month of June 2016, with 4,820 physical copies sold.