Relient K /rɨˈlaɪ.ɨnt ˈkeɪ/ is an American rock band formed in 1998 in Canton, Ohio, by Matt Thiessen, Brian Pittman, and Matt Hoopes during the band's junior year in high school and their time at Malone University. The band is named after guitarist Hoopes' automobile, a Plymouth Reliant K car, with the spelling intentionally altered to avoid trademark infringement over the Reliant name.

The group is associated with the contemporary Christian music culture, most notably the Christian rock and punk scene. The group has also performed alongside secular artists. The band has reached critical success with mainstream pop punk and alternative rock. The band's sound incorporates piano and acoustic elements. Since its formation, Relient K has released nine studio albums, seven EPs, two Christmas albums, and one collection of rarities. The band has received numerous awards including a Grammy Award nomination in 2003 for Best Rock Gospel Album and two Dove Awards.