Spencer Chamberlain (born January 4, 1983) is an American musician who is the lead vocalist for the rock band Underoath.

Although Chamberlain hadn't grown up in a Christian home and avoided religion most of his childhood, he claims it is half of what saved him, the other being music.

Chamberlain has released six albums with Underoath, They're Only Chasing Safety (2004), Define the Great Line (2006), Lost in the Sound of Separation (2008), Ø (2010), Erase Me (2018), Voyeurist (2022).

When Define the Great Line was released on June 20, 2006, it sold 98,004 copies within its first week and debuted on the Billboard 200 Chart at No. 2.

Now when Chamberlain's relating those things that eat at the edges of his conscience and his soul, he has the kind of multi-faceted caterwaul to convey that despair."

The article also comments on his songwriting, saying that it "reaches inward, confronting every ugly crevice of his being, often emerging from the clash furious and disoriented, but hopeful."

[10] Later in the year, Chamberlain announced his new band Sleepwave, along with plans for a debut single, "Rock and Roll is Dead and So Am I".

[11] In 2016, Underoath regrouped for a series of shows dubbed 'Rebirth' playing 'They're Only Chasing Safety' and 'Define the Great Line' in full.