Elsa Savira, Runtung Sitepu, Jelly Leviza, M. Hawin
Registration-based trademark systems provide clarity and legal certainty, yet they can be misused when filing priority is exploited to capture another trader’s goodwill or block legitimate market entry. This article argues that good faith should serve as a substantive safeguard against abusive first-to-file practices. This article employs prescriptive doctrinal legal research using statutory, conceptual, comparative, and case-study approaches. Drawing on Gustav Radbruch’s account of legal certainty and John Rawls’s theory of justice, the article reconstructs good faith as a corrective principle that disciplines, rather than negates, first-to-file logic. It proposes a framework for assessing bad faith based on prior knowledge of the sign, intent to appropriate goodwill, lack of genuine intent to use, strategic or blocking conduct, misleading market effects, and post-filing behavior. The Indonesian experience is situated within broader international debates from the Paris Convention and TRIPS to recent European and Chinese developments.