Dweck (1999) proposes that self-theories – a person’s beliefs about themselves - lead to differences in motivation and achievement. Although self-theories are found to be influential in children, this study examines their effects in a university, student population. Through the use of online questionnaires and replication and expansion of two previous studies, this investigation looked at the impact of self-theories on achievement; the effect inducing self-theories had on attributions and responses to failure; and the impact manipulation of self-theories had on intelligence scores after negative-feedback. Additionally, in each of the three studies it was investigated whether three alternative variables, self-esteem, grit and locus of control, were better predictors of these effects than self-theories alone. Study 1 revealed that in university students, self-theories are not predictive of achievement, however, the alternative variable self-esteem is. Study 2 showed that inducing self-theories has no effect on how failure is attributed and responded to, but revealed that both self-esteem and grit have significant effects on how attributions are made. Finally, study 3 found that neither induced self-theories, nor any of the alternative variables, are predictive of intelligence scores after negative-feedback. Together these findings indicate that, unlike children, university students’ achievement and responses to failure are not affected by self-theories, being more influenced instead by self-esteem. These results have important implications regarding how best to encourage achievement within different populations. A greater understanding of how to do so will ensure everyone has the chance to reach their potential.