The purpose of this study is to explore ethnomathematics in wedding traditions of Dayak ethnic. The type of research used in this study is a qualitative research with an ethnographic approach. This research was conducted on the Dayak Pompak'ng community, Sanggau Regency and Dayak Kanayatn Landak Regency, West Kalimantan Province. The data in this study are the forms of traditional wedding traditional tools, and traditional wedding tradition activities, while the data sources are divided into two, namely primary and secondary. The primary data sources are customary leaders and mathematics teachers, while the secondary data are the general Dayak community. Data collection techniques used in this study are direct observation techniques, direct communication techniques and documentary/bibliographical study techniques. Data collection tools used are observation sheets, interview guidelines, and documents. The data analysis technique used in this research is data reduction, data presentation, conclusion/verification. The validity checking technique used is source triangulation. Based on data analysis conducted on the findings in the field and interviews, the results of this study indicate that there are traditional wedding traditional tools and activities that have mathematical concepts in form, and use in the form of tools used, and how to use these tools. The materials in the traditional games of the Dayak Pompak'ng and Dayak Kanayatn ethnic groups are flat shapes, the Pythagorean theorem, spatial figures, calculations and sequences and series. The results showed that there was a link between local culture and mathematics learning.