Despite growing recognition of ethnomathematics as a culturally responsive approach to mathematics education, its integration into classrooms remains largely informal and inadequately documented, particularly in minority language communities. In the Philippines, Waray-speaking communities in Leyte remain underexplored in ethnomathematics literature, leaving a significant gap in culturally responsive mathematics education. Using a single case study design, this study examined the ethnomathematical practices of junior high school mathematics teachers in a rural municipality in Leyte. Data were collected through semi-structured interviews with eleven teachers and lesson plan analysis. Findings revealed that teachers employ culturally grounded instructional practices by drawing on the Waray language, local livelihoods, community spaces, and social practices as mathematical contexts. However, these practices are only selectively reflected in formal lesson documentation. Cultural contexts appear in limited lesson plan components, while the Waray language is entirely absent despite its extensive use in classroom instruction. Teachers viewed sociocultural resources positively, identifying the Waray language as a tool for facilitating mathematical understanding and engagement and cultural relevance as a driver of student participation. However, while teachers view ethnomathematics as a pathway to more transformative mathematics instruction, structural, curricular, and student-level constraints continue to hinder its sustained integration. These findings highlight the need for institutional frameworks that formally recognize and support the integration of culturally responsive practices in mathematics instruction.