The band formed in Dublin on 25 September 1976.
Larry Mullen, Jr., then 14, posted a notice on his secondary school notice board (Mount Temple Comprehensive School) seeking musicians for a new band. Seven teenage boys attended the initial practice in Mullen's kitchen. It was, as Mullen put it, "'The Larry Mullen Band' for about ten minutes, then Bono walked in and blew any chance I had of being in charge." The group featured Mullen on drums, Paul Hewson (Bono) on lead vocals, Dave Evans (The Edge) and his brother Dik Evans on guitar, Adam Clayton, a friend of the Evans brothers on bass guitar, and initially Ivan McCormick and Peter Martin, two other friends of Mullen. Soon after, the group settled on the name "Feedback", because it was one of the few technical terms they knew. Martin did not return after the first practice, and McCormick left the group within a few weeks. Most of the group's material initially consisted of cover versions, which the band said was not their forte. The original material the band did write demonstrated a sound influenced by their post-punk peers.
In March 1977, the band changed their name to "The Hype". Dik Evans, who was older and by this time at college, was becoming the odd man out. The rest of the band was leaning towards the idea of a four-piece ensemble and he was "phased out" in March 1978. During a farewell concert in the Presbyterian Church Hall in Howth, which featured The Hype playing covers, Dik ceremoniously walked offstage. The remaining four band members completed the concert playing original material as "U2". Steve Averill, a punk rock musician and family friend of Clayton's, had suggested six potential names from which the band chose "U2" for its ambiguity and open-ended interpretations, and because it was the name that they disliked the least.