China is known for using cyber weapons to pursue geostrategic goals. In recent years, entities linked to the Chinese state have carried out alleged economic espionage of commercial firms in Southeast Asia. The region is increasingly vulnerable as it is home to some of the most rapidly growing knowledge-intensive sectors in the world. To help themselves, Southeast Asian governments should be more proactive in discussing the threat of economic espionage with foreign states and committing to norms of responsible state behaviour in cyberspace.