A trademark parody is a ridicule, criticism, or satire of an idea related to a registered trademark or indication of goods or services. Traditionally, parody issues have been discussed more in the context of copyright than trademark, and there have been frequent lawsuits regarding trademark parodies around the world. A few countries have recognized the social significance of trademark parodies and, therefore, have sought protection for their use via legislation or judicial precedents. However, it is debatable whether a parody of a well-known trademark —one that has become famous through years of trademark management and capital investment— results in its dilution. Moreover, some users of trademark parodies in Japan file trademark applications to the Japan Patent Office (JPO) in order to distinguish their goods and/or services from the competition. Therefore, it is equally important to discuss whether the use of trademark parody and grant of exclusive rights through trademark registration are acceptable. As there is no legal precedent for trademark parody use in Japan, the legal systems and cases related to trademark parody use in the United States, Germany, France, and Korea were examined. When the laws, regulations, and case studies of each country are organized, the following common points are observed: (1) in the case of a successful trademark parody —that is, even when associated with the original trademark, the trademark parody, which intentionally shows that it is not a good or service related to the original trademark, and adds a new form of message of satire, ridicule, joke, etc.— there is no possibility of confusion between the parody and the original, well-known trademark; (2) infringement is likely to be affirmed if the trademark parody causes dilution due to tarnishment or pollution; and (3) infringement is likely to be denied for non-commercial parodies. However, each country has different judgments regarding the acceptability of dilution due to blurring or commercial parodies. Recently, in the United States and Europe, not only copyright parodies but also trademark parodies have been allowed. The study examined the admissibility of trademark parody under Japanese law and found that the use of a successful trademark parody is allowed in the country. In other words, according to the current Japanese Trademark Law and Unfair Competition Prevention Law, in the case of a successful trademark parody, the similarity of marks and the likelihood of confusion with the original, well-known trademark is likely to be denied and does not correspond to infringement. Additionally, even when it is considered an act of unfair competition under Article 2, Paragraph 1, Item 2 of the Unfair Competition Prevention Law because of the dilution of a well-known trademark, it should be permitted in order to protect the freedom of expression. Furthermore, in Japan, the use of the trademark parody itself sometimes does not correspond to its use as a trademark or an indication of goods or services, which is a precondition for infringement. On the other hand, regarding the registration of trademark parody, the study organized trial decisions and judicial precedents contesting the possibility of registration of trademark parody, which has been increasing in Japan, and examined the acceptability of registration of trademark parodies in Japan. Unlike the situation of use, the study concluded that it is appropriate to refuse trademark registration, even for successful trademark parodies. The reasons are as follows: (1) the registration of the trademark parody is not permitted in other countries; (2) the need to protect the freedom of expression is not crucial, but the disadvantages for the right holder of a well-known trademark are immense; (3) it is possible for parody trademark users to secure their own use and prevent the third party’s use even without registration; and (4) the Japan Patent Office has difficulty performing a uniform examination of parody trademarks. Furthermore, as for the grounds to refuse the registration of a trademark parody, it was proposed to prevent registration by applying the existing public order or morality provisions of Article 4, Paragraph 1, Item 7 of the Japanese Trademark Law, instead of legislative measures. Parody has long been popular for adding humor and satire using another person’s work. With the recent development of the Internet and social networks, the importance and frequency of parody is increasing. To respect the cultural values of parodies and achieve the purpose of trademark laws and unfair competition prevention laws—that is, industrial development and sound economic development—continuous research is required on the most appropriate methods for the use and registration of trademark parody.