We examine how selected high school characteristics – including type of diploma – contribute to students' academic success in an American-type university in the United Arab Emirates (UAE). We find no robust evidence that US, UK, and UAE systems of high school diploma produce different outcomes, once we control for English proficiency. Irrespective of the type of diploma, high school grade is a strong positive predictor of future performance. We identify significant female, nationality, and family income effects. There is evidence that school ownership (private versus public) does not matter, and that graduates of coeducational schools perform better.