This article explores the concept of academic freedom and whether it is under threat in US and UK higher education. How is "academic freedom" protected by the law in each country? What are the threats to "academic freedom"--from government micro-management of universities, from commercial sponsors of university research, from managerialism/corporatism within university governance, from political correctness on the campus, from alumni-donors and the funders? Specifically, is academic freedom within UK universities challenged by recent anti-terrorism legislation; and in the USA by the neo-conservative "Academic Bill of Rights" campaign? The conclusion is not pessimistic concerning the viability of academic freedom in both countries, but counsels wariness in watching out for threats if another McCarthy era is to be avoided. (Contains 6 notes.)