This research has been completed with the purpose to describe about the process of reduplication, the varieties of reduplication, the types of reduplication and the meaning of reduplication in Dayak Murut Tahol Language. Thus, based on the result of the research, the researcher wishes that it will gives more immense understanding about reduplication in Dayak Murut Tahol language, also it will roles the contribution as the data in primordialism language, even as the application of Indonesia linguistics knowledge into regional language, especially in Dayak Murut Tahol language. In this research, the researcher uses the descriptive qualitative method. The data collection techniques that the researcher uses are writing or noting, data selection, and data aggregation. Besides, the data analysis techniques are descriptive qualitative technique and agih method. Then, based on the research, the result are the forms of reduplication and the processes of reduplication. However, the forms of reduplication are the whole reduplication, example: lakou-lakou (jalan-jalan), and the half reduplication, example: angalap-alap (mengambil-ambil). Furthermore, the processes of reduplication are the whole-reduplication process, example: rangan-rangan, the basic form is rangan, the whole-reduplication is rangan-rangan, which means “friends”, and the half-reduplication process, example: sekunyib-kunyib, which means “smiling”, prefix se- + kunyib created the words of sekunyib-kunyib, which means “friends”. The categories of reduplication are: 1. Nomine, example: ali-ali (brothers/sisters), 2. Verb, example: lakou-lakou (walk around), 3. Adjective, example: mangit-mangit (angry), 4. Numeral, example: ruo-ruo (both). Moreover, the meanings of reduplication are, 1. Explain of plurality, example: abuk-abuk (hairs), 2. Explain of the most, example: sabuoi-buoino (forever). 3. Explain of the counterfeit, example: karita-karitaan (car-toys), 4. Explain of approximately, example: kasilou-silouan (approximately yellow/almost yellow).