This paper investigates the role of cultural belief systems in gender, socioeconomic, language and immigrant achievement gaps. The sizes of achievement gaps on the 2018 PISA tests of 79 societies from nine different cultural clusters are analyzed with two-way ANOVA along the lines of gender, socioeconomic status (SES), home language, and immigrant status. Three key findings have emerged from this study: (1) the home language and gender achievement gaps do not appear to vary with cultural belief systems; (2) cultural variations play a minimal role in the SES achievement gap in all but Confucian Asian societies; and (3) the immigrant achievement gap is less evident in Anglo and Arabic societies than in other cultures.