Despite the explosive growth in stereotype threat (ST) research over the decades, a substantive amount of variability in ST effects still cannot be explained by extant research. While some attribute this unexplained heterogeneity to yet unidentified ST mechanisms, we explored an alternate hypothesis that ST theory is often misspecified in experimental research design, which introduces experimental noise (and hence variability) in stereotype threat effects unlikely to be explained by extant moderators. This study used multilevel meta-analysis to examine the impact of ST misspecification in research design on ST outcomes. Results revealed that ST effects were artificially inflated in studies that failed to include essential conditions necessary for its occurrence. Because most studies in the meta-analysis had either excluded or partially included these conditions, findings from this study suggest that ST effects on women’s performance might be smaller than previously reported in primary and secondary (meta-analytic) studies.