This article reports on a study that explored how a group of in-service mathematics teachers integrated ethnomathematics approaches into the teaching and learning of geometry. The study used a convergent parallel mixed-methods design, which combined both quantitative and qualitative methods, to provide a deeper understanding of how the participants integrate ethnomathematics approaches into the teaching and learning of geometry. The data for the study were gathered from 40 in-service mathematics teachers through the use of questionnaires and focus group discussions. Results showed that the in-service teachers integrate ethnomathematics approaches into the teaching and learning of geometry as learning materials, resources, and the learning context. Based on the study, it is suggested that teachers should consider the incorporation of ethnomathematics approaches into the teaching and learning of geometry using technological means such as the internet, TV, and films. The findings have implications for continuous teacher professional development in the forms of workshops for the teachers involving the use of ethnomathematics approaches.