This study investigated the relation between positive affect and a variety of variables related to college success for undergraduate students matriculating at 21 academically selective 4-year colleges and universities in the United States. Positive affect-cheerfulness-is generally positively related to students' self-rated academic abilities, self-predicted likelihoods of various college outcomes, self-stated major and academic-degree intentions, and self-reported subjective college outcomes, but negatively related to most objective college-success variables (e. g., cumulative college grade-point average) recorded by the institution of matriculation, and not related to objective college outcomes reported by the student. Positive affect is thus associated with “positive illusions” about college-success variables. © 2010 Springer Science+Business Media B.V.