Formed in 2003, TVXQ were originally a five-member group consisting of Hero Jaejoong, Max Changmin, Micky Yoochun, U-Know Yunho, and Xiah Junsu.

TVXQ made their debut with one of their biggest hits, "Hug". The group, which was signed to SM Entertainment, immediately became well-known in both South Korea and Japan, where they released Japanese language albums. After years of successful songs like "O"-Jung.Ban.Hap. and Rising Sun, the boy band finally ended up with two members, U-Know Yunho and Max Changmin, as a result of a lawsuit brought by Hero Jaejoong, Micky Yoochun, and Xiah Junsu against SM over their contracts with the company.

Super Junior, also known as SJ or SuJu, is a boy band from South Korea formed by SM Entertainment. With the release of the digital single "Twins" (Knock Out) on November 6, 2005, they made their official debut.

With Kyuhyun's joining in 2006, the music act had 13 members and operated as a full group rather than a rotational concept that was initially intended, similar to how the current NCT operates. The group proved highly successful in Japan similar to TVXQ, which was a huge market for K-pop in the 2000s. Super Junior, one of the longest-lasting boy bands in K-pop, has seen a few lineup changes as members leave SM. Their most recent album, The Road: Winter for Spring, was released in February 2022.

The four-member boy group BIGBANG, known as The Kings of Kpop, is managed by YG Entertainment and features global superstars G-Dragon, T.O.P, Daesung, and Taeyang.

The group was formed through the show "Bigbang Documentary" and they made their public debut in 2006 at the YG Family's 10th Anniversary concert at Seoul's Olympic Gymnastics Arena with five members, including former members Seungri. Seungri departed the group and withdrew from the music industry during the group's 2019 hiatus, leaving them with four members. They became a highly acclaimed boy group loved by fans of many generations, not just in Korea but also internationally, thanks to the group's series of hit songs and the members' incredible talent and charisma.

Girls' Generation, popularly known as SNSD and dubbed the Queens of KPOP, is a South Korean girl group formed by SM Entertainment. Originally consisting of nine members, Jessica left the group in September 2014.

With their eponymous Korean album and the single "Into the New World", Girls' Generation made their stage debut on August 2, 2007. With the single "Gee", which held the top spot on KBS's Music Bank for a record-breaking nine consecutive weeks and was Melon's most well-known song of the 2000s decade, the group gained national attention in 2009. With the release of the follow-up songs "Genie" "Oh!" and "Run Devil Run" between mid-2009 and early 2010, Girls' Generation increased their popularity in South Korea. Oh! (2010), the group's second studio album in Korea, became the first female act to win the Golden Disc Award for Album of the Year. On May 17, 2022, SM Entertainment announced that Girls' Generation will make a comeback to promote a new album for their 15th anniversary in August

South Korean girl group and band Wonder Girls was formed by producer Park Jin-young under JYP Entertainment in 2006, and they made their debut in 2007.

The Wonder Girls of JYP Entertainment made their debut in 2007 with "Irony". The next year, when they launched their breakthrough hit "Tell Me", Yubin replaced HyunA in the group. With their single "Nobody", which peaked at number 76 on the Billboard Hot 100, the band became the first South Korean artist to do so in music history. The final lineup for the group was Yubin, Yeeun, Sunmi, and Hyerim. Hyuna quit the group in the latter part of 2007, while members Sunye and Sohee officially left in 2015.

KARA was a South Korean girl group formed by DSP Media in 2007. Nicole Jung, Han Seungyeon, Park Gyuri, and Sunghee made comprised the group's first lineup. However, Sunghee's departure a year later, with Goo Hara and Kang Jiyoung joining shortly after.

In 2009, as a five-member group, KARA made their debut with "Honey", which was followed by the hits "Lupin", "Jumping" and "Step". They continued to dominate the charts both in their home country as well as Japan. Nicole and Jiyoung left the group in 2015 when their seven-year agreement with DSP Media came to an end. After then, KARA went through a reorganization. This resulted in Heo Youngji joining the group. Kara ultimately disbanded on January 15, 2016, after over ten years of promotion.

Shinee (stylized as SHINee) was founded by SM Entertainment in 2008. The group has received multiple awards and the title "Princes of K-pop" due to their musical influence in Korea. The group is currently composed of four members Onew, Key, Minho, and Taemin. Vocalist Jonghyun, who was part of the original five-piece band, passed away in December 2017.

Shinee made their debut in May 2008 with the release of their first EP, Replay, and the track "Replay". The group received media attention for launching the "Shinee Trend," a student fashion trend. The Shinee World, the group's debut Korean studio album, was released in August 2008 and was named Newcomer Album of the Year at the 23rd Golden Disc Awards. The group was listed on the Forbes list of Korea Power Celebrity multiple times, once in 2014 and again in 2016.

2PM debuted as a seven-member group in 2008 (now they consist of 4 members: Jo Kwon, Chang-min, Seulong and Jinwoon). "Again & Again", "10 Out of 10" and "Hands Up" are all iconic songs of the band.

They made their official Japan debut in January 2012 under Sony Music Japan. The group's leader, Jaebeom (now known as Jay Park), left soon afterward in 2009. The group kept releasing songs in South Korea and Japan until several members enlisted in the military in the 2010s. Although each member is now working by a separate agency, they frequently emphasized that 2PM did not break up and that they have provisions in each of their individual contracts that would allow them to promote as 2PM in the future. They made a comeback in June 2021 with MUST, their seventh studio album.

2NE1 was a four-member girl group under YG Entertainment. On May 6, 2009, they made their debut with the song "Fire". Their name stands for "New Evolution of The 21st Century".

They were one of the most influential female groups to originate from YG Entertainment. The group was originally made public with their debut and breakthrough single "Fire", which they released after their joint single "Lollipop" with Big Bang to promote LG's Lollipop phone. 2NE1 was one of the first K-pop girl groups to go on a global tour, from Asia to North America in 2012. YG Entertainment made the announcement of the group's breakup on November 25, 2016. Their final single "Goodbye" was released on January 21, 2017.

f(x) was a five-member girl group under SM Entertainment. On September 5, 2009, they made their official debut with the digital single "La Cha Ta".

Their debut studio album, Pinocchio (2011) and two extended plays NU ABO and Electric Shock produced three number-one singles on South Korea's Gaon Digital Chart. Their widely acclaimed second studio album, Pink Tape (2013), was the only K-pop album on the "41 Best Albums of 2013" list on the US music channel Fuse, the only idol album to be included on the "Top 100 Classic Albums of All Time" list compiled by Korean critics, and it was named "Greatest K-pop Album of the 2010s" by Billboard. The group has presumably disbanded with the departures of three members in 2019. f(x) has never formally broken up, although many people refer to f(x) in the past tense.