AbstrakPenelitian ini dilakukan di Desa Jeruju Besar, Kecamatan Sungai Kakap, Kabupaten Kubu Raya. Tujuan dari penelitian ini adalah untuk mengetahui: rasionalisasi mappacci pada masyarakat etnis Bugis di Desa Jeruju Besar, Kecamatan Sungai Kakap, rasionalisasi fungsi mappacci, dan rasionalisasi makna mappacci pada masyarakat etnis Bugis di Desa Jeruju Besar, Kecamatan Sungai Kakap. Pendekatan penelitian yang digunakan adalah penelitian kualitatif dengan menggunakan metode deskriptif. Data diambil dengan menggunakan metode observasi, wawancara, dan dokumentasi. Hasil wawancara dan observasi dengan 5 informan dibagi menjadi informan kunci dan informan pendukung. Data diperoleh dengan menggunakan teknik wawancara dan observasi mendalam serta menggunakan dokumen yang relevan dengan penelitian. Dari hasil penelitian ditemukan bahwa rasionalisasi mappacci tradisional di Desa Jeruju Besar, Kecamatan Sungai Kakap memiliki beberapa prosesi, yaitu kedua mempelai yang duduk di atas lamming, membaca Al-barzanji dan Khatamul Qur'an, memasang pacci (daun pacar), dan membaca doa. -doa untuk ucapan selamat dan makan bersama rasionalisasi fungsi mappacci meliputi pedoman perilaku, kontrol sosial, dan identitas kelompok masyarakat Bugis di Desa Jeruju Besar, Kecamatan Sungai Kakap, Kabupaten Kubu Raya rasionalisasi makna mappacci tradisional meliputi aspek agama, budaya dan pendidikan.Kata Kunci: Rasionalisasi, Mappacci, Etnis Bugis AbstractThis research was conducted in Jeruju Besar Village, Sungai Kakap District, Kubu Raya Regency. The purpose of this research is to find out: the rationalization of the mappacci in the Bugis ethnic community in Jeruju Besar Village, Sungai Kakap District, the rationalization of the function of the mappacci, and the rationalization of the meaning of the mappacci in the Bugis ethnic community in Jeruju Besar Village, Sungai Kakap District. The research approach used is qualitative research using descriptive methods. Data were taken using observation, interview, and documentation methods. The results of interviews and observations with 5 informants were divided into key informants and supporting informants. The data were obtained using interview and in-depth observation techniques and using documents relevant to the research. From the results of the study it was found that the rationalization of the traditional mappacci in Jeruju Besar Village, Sungai Kakap District had several processions, namely the bride and groom sitting on a lamming, reading Al-barzanji and Khatamul Qur'an, installing pacci (henna leaves), and reading prayers. -prayers for congratulations and eat together rationalization of the function of the mappacci includes behavioral guidelines, social control, and group identity of the Bugis community in Jeruju Besar Village, Sungai Kakap District, Kubu Raya Regency rationalization of the meaning of the traditional mappacci includes aspects of religion, culture and education.Keyword: Rasionalisasi, Mappacci, Etnis Bugis