Previous research has established relationships between the Big Five personality factors, cognitive ability, and academic performance. A more recent personality trait, Honesty-Humility with its four facets (Sincerity, Fairness, Greed-avoidance and Modesty) is suggested to have predictive value especially in self-promoting behaviors. The aim of the present study was to find out whether lower Honesty-Humility would predict higher self-reported academic performance, and account for additional variance, after controlling for the Big Five and cognitive ability. The participants were Swedish 17-19 year-old students (N = 154) in late secondary high school. The results revealed a significant negative correlation between Honesty-Humility and self-estimated academic performance, mainly through low scores in the facets Sincerity and Modesty, as well as an additional 7% accounted for variance. The discussion concludes that the new trait Honesty-Humility may be a welcomed addition to the understanding of how students use self-promoting strategies in contemporary school.