Matt Thiessen is an American musician, best known as the lead vocalist and guitarist of the band Relient K. Formed in 1998, the band gained popularity for its catchy melodies and thoughtful lyrics, often blending elements of pop punk and alternative rock. Thiessen has also contributed to various projects and collaborated with other artists in the music industry. In addition to his work with Relient K, Thiessen has released solo music and written songs for other artists. His songwriting often reflects personal experiences and themes of faith, making him a notable figure in the Christian rock genre.