Isaac Brock (born in 1977 in Issaquah, Washington) is the lead singer and guitarist for the indie rock band Modest Mouse, as well as his side-project band, Ugly Casanova.

Brock had several run-ins with the law between 2000 and 2003. These included allegations of DUI, attempted murder, and rape. The two latter charges have since been dropped. The attempted murder charge was applied as a result of a drunk driving incident, in which a friend was injured (though not severely). The rape charge, according to Brock, was a case of "he-said/she-said" and a complete farce. The facts seem to support this; police gave the case little attention and seemed to dismiss it. However, the incident received a fair amount of press and greatly damaged Brock's reputation in the liberal Seattle indie scene. An interview with Brock can be found here: http://www.theonionavclub.com/feature/index.php?issue=4014

Brock currently resides in Portland, Oregon.