The cultural differences hypothesis is the assertion that there are large differences between Whites and racial/ethnic minorities in the United States, while there are small differences between- (e.g., African Americans and Latinos) and within- (e.g., Latinos: Mexican Americans and Cuban Americans) minority groups. Conversely, the cultural similarities hypothesis argues that there are small differences between Whites and minorities, and these differences are equal or smaller in magnitude than differences between and within minorities. In this study, we conducted a second-order meta-analysis focused on psychopathology, to (a) test these hypotheses by estimating the absolute average difference between Whites and minorities, as well as between and within minorities, on levels of psychopathology, and (b) determine if general and meta-analytic method moderators account for these differences. A systematic search in PsycINFO, Web of Science, and ProQuest Dissertations identified 16 meta-analyses (13% unpublished) on 493 primary studies (N = 3,036,749). Differences between Whites and minorities (d+ = 0.23, 95% confidence interval [0.18, 0.28]), and between minorities (d+ = 0.30, 95% confidence interval [0.12, 0.48]) were small in magnitude. White–minority differences remained small across moderators. These findings support the cultural similarities hypothesis. We discuss their implications and future research directions.