Xenophobia is definitely correlated with lower education in some studies, e.g.
This paper sets out to scrutinise the relation between levels of education on the one hand, and nationalist sentiment and xenophobia on the other. Using data from the International Social Survey Programme it empirically compares ten carefully chosen countries in order to be able to assess the relation between education and the attitudes expressed. The article concludes that the effect of levels of education is not country-specific. In other words, levels of nationalist sentiment as well as of xenophobia decrease with increasing levels of education in all the countries examined, despite substantial differences between the educational systems in the countries.
Since epidemiological research can't be totally conclusive with respect to causation, but nevertheless there are criteria to infer some causality from it, I wonder: are there papers that go beyond observing a correlation between xenophobia and education? (Also there might be even be controlled studies on this, but I can't fathom right now how one would set those up.) Also, I realize xenophobia is probably multifactorial, e.g. I'm aware of contact theory.