Duckworth, Peterson, Matthews, and Kelly (2007) defined "grit" as one's passion and perseverance toward long-term goals. They proposed that it consists of 2 components: consistency of interests and perseverance of effort. In a high school and college student sample, we used a multidimensional item response theory approach to examine (a) the factor structure of grit, and (b) grit's relations to and overlap with conceptually and operationally similar constructs in the personality, self-regulation, and engagement literatures, including self-control, conscientiousness, cognitive self-regulation, effort regulation, behavioral engagement, and behavioral disaffection. A series of multiple regression analyses with factor scores was used to examine (c) grit's prediction of end-of-semester course grades. Findings indicated that grit's factor structure differed to some degree across high school and college students. Students' grit overlapped empirically with their concurrently reported self-control, self-regulation, and engagement. Students' perseverance of effort (but not their consistency of interests) predicted their later grades, although other self-regulation and engagement variables were stronger predictors of students' grades than was grit.