This interpretivist study employed a qualitative multiple-embedded case study to examine the infusion of Gross National Happiness (GNH) values in teaching Mathematics. The study aimed to gain insights into Mathematics teachers' perceptions, understandings and practices of GNH values in Bhutanese classrooms. The study involved 10 teachers teaching Mathematics in grades XI and XII (age 16 to 18 years) students from five schools in eastern Bhutan using purposive sampling. The data collected through semi-structured interviews, classroom observations and field notes were analysed thematically. The study found that teachers have limited knowledge, skills and strategies required to explicitly infuse GNH values into Mathematics. First, the majority of teacher participants have not participated in any professional development programme related to GNH. Second, some teacher participants who participated in the GNH professional development programme did not receive clear guidance on how to plan and conduct lessons with GNH values in Mathematics. Third, the majority of the teachers face difficulty relating the concept of Mathematics to GNH. The knowledge generated from the study can contribute to the empirical baseline for future researchers related to GNH and Mathematics education. The study recommends research on factors affecting the infusion of GNH values in teaching Mathematics