Westlife, the Irish boy band formed in 1998, became one of the best-selling music groups of all time, known for their heartfelt ballads and smooth harmonies. With hits like Flying Without Wings and You Raise Me Up, they dominated the charts in the UK and Ireland. What fans may find interesting is that they hold the record for the most consecutive number-one debuts in the UK Singles Chart, with their first seven singles all reaching the top spot—a feat unmatched by any other artist.

Boyz II Men, the legendary R&B vocal group, dominated the ‘90s with their smooth harmonies and emotional ballads. Their hit End of the Road spent a record-breaking 13 weeks at number one, a feat that was later surpassed by only a few artists, including themselves with One Sweet Day in collaboration with Mariah Carey.

*NSYNC, led by Justin Timberlake, became one of the biggest boy bands ever, with No Strings Attached selling over 2.4 million copies in its first week, a record that stood for 15 years.

Take That, the British boy band that launched in 1990, became one of the UK’s most successful pop groups. With members including Gary Barlow, Robbie Williams, and Mark Owen, they had a string of hits like Back for Good and Never Forget. What fans might love to know is that their comeback in the mid-2000s was so successful that they even surpassed their original ‘90s fame, with their reunion tour in 2009 becoming one of the highest-grossing tours in UK history.

One Direction, formed on The X Factor UK, became the defining boy band of the 2010s. Fans may love knowing that they originally auditioned as solo artists and were only grouped together by Simon Cowell—a decision that changed music history.

JLS, the British group from The X Factor, achieved massive success in the UK. A fun fact is that they were the first X Factor contestants to score five number-one singles, proving their lasting appeal.

The Beatles, arguably the greatest band of all time, started out as a boy band before evolving into rock legends. They were actually rejected by a record label early in their career, being told that “guitar groups are on their way out.”

East 17, known for their edgier take on boy band pop, once outsold Take That in the UK. Their Christmas single Stay Another Day remains a seasonal favorite decades later.

The Jackson 5, led by a young Michael Jackson, set the template for future boy bands. A fun fact is that they were the first group to have their first four singles hit number one on the Billboard Hot 100.

Backstreet Boys, one of the best-selling boy bands in history, defined the ‘90s with hits like I Want It That Way. They hold the unique record of having the best-selling boy band album of all time, Millennium, which sold over 24 million copies.

LFO (Lyte Funkie Ones) was best known for their 1999 summer hit Summer Girls, which featured quirky lyrics referencing Abercrombie & Fitch and New Kids on the Block. The trio blended pop and R&B influences, creating a sound that stood out in the late '90s boy band wave. A lesser-known but fascinating fact is that they originally started as a rap group before shifting to pop, which explains their distinct lyrical flow compared to other boy bands of their time.

98 Degrees, known for their smooth R&B-influenced sound, carved their niche in the late ‘90s alongside Backstreet Boys and *NSYNC. Unlike many of their peers, they were not assembled by a record label but rather came together organically, proving that raw talent and determination could break through in a heavily manufactured industry.

5 Seconds of Summer (5SOS), the Australian pop-rock band, gained massive attention when One Direction brought them on tour. They hold the distinction of being the first band to have their first three albums debut at number one on the Billboard 200, proving their crossover appeal between pop and rock audiences.

O-Town, the boy band formed from the reality show Making the Band, gave the world hits like All or Nothing. While they followed the traditional boy band formula, what sets them apart is that they were the first group to ever be formed on reality television, paving the way for future music competition winners.

The Jonas Brothers, initially formed in the mid-2000s, became Disney Channel darlings with their infectious pop-rock hits. What’s amazing is that they actually got their start by accident—originally, only Nick Jonas was pursuing a solo career, but when a record executive heard the three brothers harmonizing, they were signed as a band instead.

Hanson, known for their infectious hit MMMBop, were different from other boy bands in that they played their own instruments and wrote their own songs from the very beginning. Their blend of pop and rock set them apart from the heavily choreographed groups of their era.

BTS (방탄소년단), the global K-pop phenomenon, revolutionized the industry with their storytelling, intricate choreography, and deep fan engagement. Despite their massive fame, they started under a small, struggling label, BigHit Entertainment, proving that passion and talent could overcome industry biases.

New Kids on the Block, the boy band that pioneered the modern formula, paved the way for every boy band that followed. What many don’t know is that their original name was actually Nynuk, but their label forced them to change it before releasing their debut album.

Big Time Rush, formed in 2009 through the Nickelodeon show of the same name, captured the hearts of young fans with their energetic music and fun-loving personas. Unlike many other TV-formed bands, they gained legitimacy as a real touring act, selling out arenas worldwide. A cool fact is that they were initially only meant to be a fictional band for the show, but due to their overwhelming popularity, they transitioned into a real-life group, recording multiple albums.

B2K (Boys of the New Millennium) rose to fame in the early 2000s with their smooth R&B tracks, including Bump, Bump, Bump featuring P. Diddy. The group, led by Omarion, became known for their impeccable choreography and youthful energy. Fans might be surprised to learn that they starred in the cult classic dance film You Got Served, which became a defining movie of the street dance era and showcased their real-life dance skills.

2gether, the fictional boy band created for an MTV movie in 2000, satirized the boy band craze with their hilariously catchy songs like U + Me = Us (Calculus). Despite being a parody, they actually gained a legitimate fanbase and even toured as a real band. A fun twist is that they were the first fictional group to land on the Billboard charts, proving that their spoof of the industry was so well done that it became reality.

Brockhampton, the self-proclaimed "boy band" formed in 2015, redefined the concept by blending rap, pop, and alternative sounds. With their diverse lineup and experimental style, they quickly gained a cult following. What makes them stand out is that they weren’t manufactured by a label but rather came together through an online Kanye West fan forum, proving that a shared passion for music can create something groundbreaking.

The Monkees were originally created as a television band in the 1960s but soon became a real, chart-topping act with songs like I'm a Believer. What’s fascinating is that while they were cast as actors to portray a band, they eventually took control of their own music, proving their legitimacy as artists rather than just TV stars.

Menudo, the Puerto Rican boy band, was known for its revolving-door membership policy, which allowed them to stay relevant for decades. One of its most famous alumni is Ricky Martin, who started his career in the group before becoming a global superstar.

New Edition, one of the pioneers of modern boy bands, set the stage for groups like *NSYNC and Backstreet Boys. A cool fact is that they were essentially the blueprint for the boy band-to-solo-artist pipeline, with Bobby Brown, Ralph Tresvant, and Bell Biv DeVoe all launching successful careers post-group.