This paper examines how Macau, with a different political and legal system under the “one country, two systems” principle, fits into China’s securitization and what impact that has on its local governance. We argue that in recent years Macau’s legal system has gradually transformed into a means of social control. Through case files related to the Assembly and Demonstration Law drawn from the Court of Final Appeal, we demonstrate that although Macau is unlike Hong Kong, where dissidents are subject to severe repression, Beijing’s emphasis on national security has weakened the checks-and-balances function of Macau’s legal system and substantially narrowed the scope of freedom of speech, even though it is nominally guaranteed and protected by the Basic Law.