No Regret Life was a Japanese rock band formed in Kanoya, Kagoshima Prefecture, in January 2001. The group was active until their disbandment in July 2013. The founding members were Kazusō Oda, Ryūta Hashiguchi, and Yuka Shimokariya. Shimokariya later left the group and was replaced by Genta Matsumura. The final and best-known lineup consisted of Kazusō Oda on vocals and guitar, Ryūta Hashiguchi on drums and backing vocals, and Genta Matsumura on bass and backing vocals.

The band began their career by playing live shows and independently releasing their first full-length album, Tomorrow is the Another Day, in November 2002. Their early activities included a tour with the prominent punk rock band Ellegarden in May 2003. In April 2004, they released a mini-album titled My Life, My Song, My Mind. Their commercial breakthrough came in February 2005 when they signed with Yeah! Yeah! Yeah! Records and released their first major maxi-single, Melody. The band's second single, Nakushita Kotoba (失くした言葉), released on June 8, 2005, became their most internationally recognized work. The song was selected as the ninth ending theme for the popular anime series Naruto, being used from episode 129 to episode 141. This connection to a major anime provided the band with significant exposure. Following this success, they released the single Ano Hi no Mirai (あの日の未来) on November 2, 2005. Their second album, Sign, which included the Naruto ending theme, was released on February 1, 2006.

Over the following years, No Regret Life continued to release music at a steady pace. They issued the singles Akogare no Hate (憧れの果て) in July 2006, Migite no Arika (右手の在処) in November 2006, and Day by day in February 2007. Their third album, Allegro, was released on March 14, 2007. After a brief hiatus from new releases, the band returned with the single Can't Explain on August 13, 2008, followed by their fourth album, Wheels of Fortune, on October 22, 2008. In July 2010, the band started their own independent record label, spiral-motion. Their final album, Discovery, was released on September 21, 2011. The band's activities came to an end when bassist Genta Matsumura announced his departure in December 2012, stating he no longer had the strength to continue. Following discussions, the remaining members decided to disband, holding a final farewell tour, Last Tour 2013 Memory & Record, which concluded in July 2013.

The musical identity of No Regret Life was rooted in rock music, characterized by Kazusō Oda's distinctive, slightly husky, and emotive vocal style. As the band's primary vocalist and guitarist, Oda was also the main songwriter, composing and writing lyrics for the vast majority of their catalog. Their sound, while energetic, often carried a melancholic and introspective quality, which made their music a fitting match for anime themes and other media. In addition to their work for Naruto, other songs by the band were used in various television programs. Ano Hi no Mirai served as the November 2005 opening theme for the TBS program Count Down TV. In 2007, the same song was used as an ending theme for Mainichi Broadcasting System's coverage of the national high school baseball championship, Minna no Koshien. Their later single, Can't Explain, was used as the August 2008 ending theme for FM Iwate's morning program, Asa no Peppermint Time. The band's industry significance rests on their career as a major-label rock act in the mid-2000s, with their legacy primarily tied to their contribution to the Naruto anime soundtrack, which has continued to introduce new listeners to their music long after the band's disbandment.