Does the basic trait Honesty-Humility predict the type of moral concerns people express in language? We explore whether Honesty-Humility relates to the expression of five moral concerns in language—namely, care/harm, justice/fairness, loyalty/betrayal, authority/subversion, and sanctity/degradation—as conceptualized by the Moral Foundations Theory. Using Natural Language Processing, we screened 16,497 (un)ethical justifications—i.e., reasons for behaving (un)ethically—for the presence of the five moral concerns (N = 901). We found that Honesty-Humility related positively to justice/fairness concerns, but it did not relate to care/harm, loyalty/betrayal, authority/subversion, and sanctity/degradation concerns. Our findings thus suggest that justice/fairness concerns might serve as one of the mechanisms relating Honesty-Humility to anti- and prosocial behavior.