Many studies have found that males, on average, perform better than females in mathematics, although the size of this gender gap is small and varies considerably across countries. Stereotype threat has been proposed as a principal cause of this gender gap. From this perspective, females' performance is affected by fear of confirming a negative stereotype about females' mathematical ability and this stereotype can be activated by an experimental manipulation that reminds females of the stereotype. Yet, evidence of a stereotype threat effect on mathematics performance in childhood and adolescence has been mixed. The present study replicated a highly cited study of stereotype threat among Italian adolescents with a much larger sample of Italian ninth grade (89 male, 75 female, mean age = 14.2) and eleventh grade (84 male, 80 female, mean age = 16.2) public high school students. Performance in tests administered both before and after the experimental manipulations were analyzed with a series of logistic mixed-effects models. Model comparisons confirmed that males performed better than females, but the probability of a stereotype threat effect was infinitesimal. We conclude that Italian adolescent gender differences in mathematics may not be explained by stereotype threat effects.