Many well-known trademarks registered by bad applicants (bad faith registrants) still qualify for registration at the Directorate General of IPR (Directorate General of Intellectual Property Rights). For example, the Hakubaku trademark from Japan is incomplete with the Hakubaku trademark from Indonesia. This study aims to determine the causes of trademark passing offs. The research method of this writing is normative law using a statutory approach and a conceptual approach. Based on this research, the results obtained in the form of factors that cause the occurrence of trademark Passing Off, namely because there are no registered Trademark Philosophy requirements, there are multiple interpretations of well-known trademark and similarities in essence or their entirety, there is still well-known trademark that is not registered with the Director-General of IPR in Indonesia so that they have the opportunity to be registered. by other persons/parties or legal entities with bad intentions, there is inaccuracy by the mark examining agency on a registered mark, and mark examiners who have multiple interpretations and are inconsistent in implementing Article 6 paragraph 1 letter a of Law Number 20 the Year 2016 on Trademark and Geographical Indications.