The goal of this study was to examine the relationships among self-determination, mental illness, and GPAs of university students. Participants were 375 undergraduate students at a large state university. Two instruments based on Self-determination theory were used in this study: the Basic Needs Scale (see Baard, Deci, & Ryan, 2004) and the Learning Self-Regulation Questionnaire (Black & Deci, 2000). Data were collected via a web-based survey. Several of the self-determination indicators were significant predictors of GPA at [alpha] = 0.01. The GPAs of students who reported having a mental illness did not differ from their peers without mental illness. For students with similar levels of self-determination, having a mental illness was not predictive of GPA. (Contains 5 tables.)