Penelitian ini membahas mengenai penerapan asas hukum first to file dalam kasus hak merek antara PS Glow dengan MS Glow dalam Putusan Pengadilan Nomor 2/Pdt.Sus.HKI/Merek/2022/PN.Niaga Sby. Dalam kasus tersebut, hakim dalam putusannya tidak menerapkan asas first to file sebagaimana diatur dalam Pasal 1 Angka (5) Undang-Undang Republik Indonesia Nomor 20 Tahun 2016 tentang Merek dan Indikasi Geografis. Tipe penelitian yang digunakan dalam penelitian ini adalah tipe penelitian Yuridis Normatif, yaitu tipe penelitian yang dalam pengolahan bahan hukum dilakukan melalui studi pustaka. Penelitian ini bertujuan untuk menelaah terkait penerapan asas first to file dalam kasus hak merek di Indonesia. Dalam penanganan perkara hak merek harus menerapkan asas first to file. Apabila terjadi pelanggaran merek, maka pemegang hak atas merek berhak mendapatkan perlindungan hukum baik secara represif maupun preventif. / The main problems in this study are discusses about the application of first to file legal principles in the case of trademark rights between PS Glow and MS Glow in Court Decision Number 2/Pdt. Sus. HKI/Brand/2022/PN. Niaga Sby. In that case, the judge in his decision did not apply the first to file principle as stipulated in Article 1 Numbers (5) of the Republic of Indonesia Law Number 20 of 2016 concerning Brands and Geographical Indications. The type of research used in this study is the Normative Juridical Research type, namely the type of research in the processing of legal materials which is carried out through library research / literature study. This study aims to examine the application of first to file principles in the case of brand rights in Indonesia. In handling rights cases, the brand must apply first to file principles. In the event of a trademark infringement, the trademark right holder is entitled to legal protection both repressive and preventive.