I.O.I

I.O.I is a project girl group that, despite being active for less than a year, left a deep mark on K-pop. Formed through Mnet's Produce 101 in 2016, the eleven members were selected by public vote from 101 trainees across 46 agencies. Their debut EP Chrysalis and single "Dream Girls" arrived in May 2016, quickly landing them on the charts. The group's sub-unit dropped "Whatta Man" in August, a bold remake of a 1968 soul classic that climbed to number 2 on the Gaon Digital Chart. Their second EP Miss Me? gave them their first number-one hit, "Very Very Very," in October.

The group's contract ended in January 2017, but not before releasing the ballad "Downpour" and holding a three-day farewell concert, Time Slip – I.O.I. They disbanded on January 29, 2017, with members returning to their original agencies. Nine years later, in May 2026, all eleven reunited for a tenth anniversary comeback with the EP I.O.I: Loop and single "Suddenly," which became their second number-one hit on the Circle Digital Chart. Today, I.O.I is remembered as the blueprint for project groups in K-pop, a fleeting but powerful collective whose members went on to become solo stars, group leaders, and household names in their own right.[edit]

In late 2015, Mnet announced a new survival show: Produce 101, where 101 female trainees from 46 entertainment companies would compete to debut in a temporary group. The concept was unprecedented in K-pop. For three months, from January 22 to April 1, 2016, viewers voted weekly, whittling down the contestants. The live finale on April 1 revealed the final eleven: Jeon So-mi, Kim Se-jeong, Choi Yoo-jung, Kim Chung-ha, Kim So-hye, Zhou Jieqiong, Jung Chae-yeon, Kim Do-yeon, Kang Mi-na, Lim Na-young, and Yoo Yeon-jung.

The group was named I.O.I, short for "Ideal of Idol." YMC Entertainment took over management, and the members moved into shared dorms, some leaving their original groups temporarily. Jung Chae-yeon was originally a member of DIA and promoted with both groups simultaneously for a period in 2016. The pressure was immense: they had just over a month to prepare their debut. On May 4, 2016, I.O.I released Chrysalis, an EP whose title symbolized their transformation from trainees to butterflies. The lead single "Dream Girls" was an upbeat, empowering track that reached number 7 on the Gaon Digital Chart.

The group's rapid rise was a testament to the power of the Produce 101 format. Within weeks, they were booked on variety shows, CFs, and music programs. In August, a five-member sub-unit consisting of Jeon So-mi, Kim Chung-ha, Kim So-hye, Zhou Jieqiong, and Kim Do-yeon released "Whatta Man," which peaked at number 2. Their second EP Miss Me? in October featured "Very Very Very," a song written by Shinsadong Tiger that became their first number-one hit. By January 2017, the group had released "Downpour," a ballad written by SEVENTEEN's Woozi, and held their farewell concert at Jangchung Arena in Seoul from January 20 to 22. Their contract ended on January 29, 2017, exactly 10 months after debut.[edit]

I.O.I's sound evolved quickly across their short career. Their debut EP Chrysalis leaned into bright, youthful pop with energetic choruses and synchronized choreography. "Dream Girls" was a classic girl-group anthem about chasing dreams, built on a catchy synth hook. The sub-unit's "Whatta Man" marked a sharp turn: a reinterpretation of Linda Lyndell's 1968 soul track, it swapped innocence for confidence, with a heavy bassline and rap verses that showcased the members' versatility.

Their second EP Miss Me? doubled down on addictive pop with "Very Very Very," a song built on a repetitive, earworm melody and playful lyrics. The track's production was crisp and modern, with a driving beat that made it a dance-floor favorite. Their final single "Downpour" showed a softer side: a sentimental ballad with piano and strings, it highlighted the vocal prowess of Kim Se-jeong and Yoo Yeon-jung. The 2026 reunion EP I.O.I: Loop returned to a fresh, energetic sound with "Suddenly," blending synth-pop with a nostalgic 2010s K-pop vibe. Lyrically, the group often explored themes of youth, ambition, and friendship, but also tackled heartbreak and longing in their later releases.[edit]

I.O.I is widely credited with pioneering the "project group" model in K-pop, where members from different agencies collaborate for a fixed period. Their success proved that temporary groups could achieve commercial and critical acclaim, paving the way for acts like Wanna One, Iz*One, and Kep1er. The group's formation via Produce 101 also revolutionized the idol audition landscape, making fan voting a central part of the debut process.

Beyond the industry structure, I.O.I influenced fashion trends in South Korea. Jeon So-mi's "center" styling, often featuring bold hair colors, chokers, and crop tops, became a template for aspiring idols. Kim Se-jeong's chic, minimalist looks were widely copied. The group also served as honorary ambassadors for the 2016 Korea Brand & Entertainment Expo and participated in cultural exchange events in Japan and China, boosting Hallyu exports. Their 2026 reunion, nine years after disbandment, was unprecedented for a project group and demonstrated the enduring bond between the members and their fandom, Melo.[edit]

I.O.I's official fandom name is Melo, short for "melody," symbolizing the harmony between the group and their fans. The official fan color is Pastel Lavender, a soft purple that appears on lightsticks, banners, and fan projects. The lightstick, released in 2016, is a translucent lavender cube with the I.O.I logo at its center, emitting a gentle glow during concerts.

Melo traditions include the "Melo Wave," a coordinated fan chant performed during live shows, and annual charity donations on the group's debut anniversary, May 4. In 2026, Melo organized a global streaming party for the reunion EP I.O.I: Loop, helping "Suddenly" top the charts. The fandom is known for its loyalty, having waited nearly a decade for the group's return.[edit]

I.O.I stands for "Ideal of Idol." Their debut EP Chrysalis was named to symbolize the members' transformation from trainees into butterflies. Kim Se-jeong served as leader only during debut promotions; the group operated without a fixed leader afterward. Yoo Yeon-jung, the youngest, later debuted with WJSN (Cosmic Girls). The sub-unit single "Whatta Man" was a rare K-pop cover of a classic 1968 R&B track. During their 2026 reunion, the group performed a medley of hits at the Mnet Asian Music Awards, receiving a standing ovation. All eleven members reunited for the comeback despite being under different agencies. The reunion EP I.O.I: Loop sold over 300,000 copies in its first week, setting a record for highest first-week sales for a project girl group. "Suddenly" accumulated over 50 million streams on Spotify within its first month of release.[edit]