Using data gathered during a case study of the "culture" of a Jewish secondary school, this article explores the indeterminate boundaries of Jewish identity. By examining the mechanisms that control what and who comes into the school, and what is approved and disapproved of in the school, a picture emerges of what and who is counted as "Jewish". There is detailed consideration of the admissions policy, the rules about kosher food, the explicitly religious symbols in use, the importance of Israel and the contested issue of McDonald's. Sometimes the boundaries are very clear-cut, but in some cases there is ambiguity and disagreement that make the frontiers of English Jewish student identity decidedly fuzzy. (Contains 7 notes.)