Stereotype threat has been proposed as 1 potential explanation for the gender difference in standardized mathematics test performance among high-performing students. At present, it is not entirely clear how susceptibility to stereotype threat develops, as empirical evidence for stereotype threat effects across the school years is inconsistent. In a series of 3 studies, with a total sample of 931 students, we investigated stereotype threat effects during childhood and adolescence. Three activation methods were used, ranging from implicit to explicit. Across studies, we found no evidence that the mathematics performance of school-age girls was impacted by stereotype threat. In 2 of the studies, there were gender differences on the mathematics assessment regardless of whether stereotype threat was activated. Potential reasons for these findings are discussed, including the possibility that stereotype threat effects only occur in very specific circumstances or that they are in fact occurring all the time. We also address the possibility that the literature regarding stereotype threat in children is subject to publication bias.