The search for “noncognitive” skills essential for workforce readiness has largely overlooked one important individual difference domain: interests. This chapter reviews evidence for the relationship between interests and job performance, career success, and academic achievement. It also discusses two mechanisms through which interests can predict a range of educational and work outcomes. First, interests serve as a source of intrinsic motivation that drives the direction, effort, and persistence of human behaviors. Specifically, interests contribute to learning and the acquisition of job knowledge, which are direct determinants of academic and job performance. Second, interests capture the relationship, or the fit, between a person and an environment. The degree of person–environment fit in terms of interests, or interest congruence, predicts academic and work outcomes above and beyond individual interest scores alone. In closing, the chapter discusses the implications of using interest assessments for educational and career guidance and for personnel selection.