People view many attributes, including intelligence, through implicit theories (or mindsets). Entity mindsets position the attribute as unchangeable or static, whereas incremental mindsets see the attribute as malleable or capable of being changed/improved (Dweck & Leggett, 1988). The present studies examined a new questionnaire designed to measure implicit theories of academic success in undergraduate students (the Academic Beliefs Scale, ABS) and its relationship to academic achievement (specifically grade point average, GPA). In Study 1, a negative relationship between the entity theory of academic success and GPA was mediated by poor study habits, procrastination, and self-handicapping while the positive relationship between the incremental theory of academic success and GPA was mediated by poor study habits. In Study 2A and 2B, the validity and reliability of the ABS were evaluated, with generally satisfactory findings. Study 2B also conceptually replicated the findings of Study 1, finding that another unique set of behaviors, good academic habits, mediated the relationship between the incremental theories of academic success and GPA. Future research with undergraduates should continue to examine implicit theories of academic success as a predictor of additional academic outcomes and the psychometric properties of the ABS.