11 September 2021 marked 20 years since the September 11 attacks on New York City and Washington DC. In this article, we map Australia’s legal responses to terrorism across those two decades. We report the total number of counterterrorism laws enacted by the federal Parliament and the average time taken for parliamentary debate. Afer recapping laws from the first decade, we focus on the second decade of lawmaking, setting out key powers and offences and assessing how the laws have been interpreted by courts and reviewed by independent bodies. Finally, we identify recurring themes and challenges from the second decade. Te sheer volume of laws, their scope, and their speedy passage through Parliament raise significant concerns for fundamental rights and the health of Australia’s democracy.