I Don't Like Mondays. (IDLMs.) is a Japanese rock band based in Tokyo. The band members are Yu (vocals), Choji (guitar), Kenji (bass guitar), Shuki (drums). Founded in 2012, the band has released several self-produced albums and singles, including the One Piece anime theme song "Paint".

The band focuses on creating high energy dance music with memorable choruses and a light feeling that can take away the burdens of everyday life, including the "Mondays" referenced in their name.

In addition to several tours of Japan, the band has performed internationally at festivals in Jakarta, Sao Paulo, Taipei, and Barcelona. Their music has been used for the television dramas Rizzoli & Isles and Octo: Mind Investigator Akari Shinno.

The band is also deeply involved in the fashion industry and has collaborated with Versace, H&M, Emporio Armani, and Leslie Kee, among others, along with launching their original fashion brand.

They are signed with Rhythm Zone, an imprint of Avex Group.