As suggested by the Minorities' Diminished Returns (MDR) theory, socioeconomic status (SES) systemically results in smaller outcomes for non-Whites compared to Whites. We still know very little about diminished trans-generational returns of SES resources such as parental educational attainment (PEA).This cross-sectional study explored racial variation in the effect of PEA on the college students' grade point average (GPA) in the US.The Healthy Mind Study (HMS, 2016-2017) is a national telephone of college students in the US. The total sample was 18,072 domestic undergraduate college students who were either non-Hispanic Whites ( = 16,718; %92.50) or non-Hispanic Blacks ( = 1,354; %7.50). The independent variable was PEA. The main outcome was GPA measured using self-reported data. Age, gender, sexual orientation, transgender status, and financial difficulty were covariates. Race/ethnicity was the effect modifier. Linear regression models were used to analyze the data.Overall, higher PEA was associated with a higher GPA, independent of all possible confounders. Race/ethnicity, however, showed a significant interaction with PEA on students' GPA, indicating a smaller positive effect of PEA on non-Hispanic Blacks compared to non-Hispanic Whites college students' GPA. Race/ethnicity stratified models also showed a larger effect for White than Black students.The boosting effect of PEA in GPA is smaller for Black compared to White college students. US should systematically reduce extra costs of upward social mobility for racial and ethnic minority families.