ABSTRAK Kebutuhan mendesak terkait optimalisasi kualitas produk dan daya saing suatu perusahaan di tengah persaingan pasar yang ketat menjadi alasan utama dilakukan penelitian ini. Tingginya tingkat cacat dan kerusakan produk berdampak pada peningkatan biaya produksi, rusaknya reputasi perusahaan serta turunnya kepuasan pelanggan. Untuk mengatasi masalah ini, penelitian menerapkan metode Six Sigma dengan pendekatan DMAI (Define, Measure, Analyze, Improve) pada PT. RM, sebuah perusahaan patungan Jepang-Indonesia di industri furnitur. Hasil dari tahap define mengidentifikasi cacat utama, yaitu pecah V-Cut 49% dengan persentase 49% dari total cacat. Tahap measure menunjukkan tingkat cacat produk melebihi target optimal, dengan DPMO sebesar 47.667 dan nilai sigma rata-rata 3,2. Melalui tahap analyze, ditemukan faktor utama penyebab cacat, yakni ketidaksesuaian proses pemotongan, kebersihan material, dan kurangnya kontrol kualitas. Solusi pada tahap improve mencakup perbaikan prosedur kerja, pelatihan karyawan, dan pemeliharaan rutin mesin. Hasil penelitian diharapkan mampu mengurangi frekuensi cacat produk, meningkatkan efisiensi operasional, dan memperkuat daya saing PT. RM di pasar domestik maupun internasional, serta mendukung keuntungan jangka panjang bagi perusahaan ABSTRACT The urgent need to optimize product quality and a company’s competitiveness amid intense market competition is the primary motivation for this research. High defect and damage rates increase production costs, damage the company’s reputation, and reduce customer satisfaction. To address this issues, this study applies the Six Sigma methodology using the DMAI (Define, Measure, Analyze, Improve) approach at PT RM, a Japanese-Indonesian joint venture in the furniture industry. In the define stage, the main defect identified was V-Cut breakage, accounting for 49% of total defects. The measure stage revealed that the product defect rate exceeded the optimal target, with a DPMO of 47,667 and an average sigma value of 3.2 The analyze stage identified inconsistencies in the cutting process, material cleanliness issues, and inadequate quality control as the primary causes of defects. To address these problems, the improve stage proposed solutions such as refining work procedures, conducting employee training, and implementing routine machine maintenance. The study’s findings are expected to reduce product defect frequency, enhance operational efficiency, and strengthen PT RM's competitiveness in domestic and international markets, ultimately supporting the company’s long-term profitability.