Previous research has established that undergraduate students in the UK who had attended private schools perform less well at university, on average, than equivalent students who had been educated at a state school prior to university (Smith and Naylor, 2001 and 2005; Crawford, 2014a). This well-known result has provided an evidence base for the use of contextualised offers in admissions across the sector (Schwartz Report, 2004; Hubble and Bolton, 2020) as an instrument for enhancing social mobility. In the current paper, we use a rich dataset for a particular university to examine whether the negative association between private schooling and class of degree awarded holds across all students, independent of ethnicity: we find that it does not. For White students, we obtain the standard result that private schooling is associated negatively with class of degree. However, in stark contrast, among students whose ethnicity is self-reported as either Black, Asian or Mixed Ethnicity, attendance at a private school prior to university is, on average, associated positively with the class of degree awarded. On further exploration, we find this is driven by a strong positive association among Black students and students of Mixed Ethnicity; the overarching category of Black, Asian and Minority Ethnicity conceals substantive differences within the category. Among Asian students, the absence of any association between private schooling and degree class, on average, masks a very strong negative association for those from lower socioeconomic status backgrounds. We discuss and interpret our results in the context of hypotheses within the literatures on schooling effects and on the ethnicity awarding gap in higher education.