This study aimed to examine the underlying causes of poor performance in mathematics among class VI students in Samtse Dzongkhag. The sample consisted of 219 students (110 girls &109 boys) and 6 mathematics teachers (3 male & 3 female), which were selected from the population of 8 schools in Samtse Dzongkhag. A mixed-methods design was employed for the study. Survey questionnaires and interviews were used to collect data. The mean and standard deviation were used in the analysis of the survey data. The results of the data analysis included survey results and interview results. The findings of the study led to the conclusion that improper teachers’ approaches, inadequate supervision, inadequately qualified teachers, inadequate teaching materials and facilities, and a lack of parental involvement contribute to the causes of poor performance in mathematics in the study area. The study also found that developing students’ attitudes, training mathematics teachers, effective teaching methodologies, available TLM, classroom and library facilities, administration supervision, parental involvement, technology integration, and constant constructive assessments are the ways of improving performance in mathematics in the study area. The study recommended that teachers should focus on adopting constructive assessment practices; teachers should make efforts to develop a positive attitude towards mathematics among students; teachers should utilize suitable teaching methods for mathematics instruction; adequate supervision and inspection of teaching and learning practices should be ensured; and administrators should make efforts to address the shortage of qualified mathematics teachers. Schools should ensure the provision of sufficient teaching materials and resources for mathematics teachers. Parents should be encouraged to get involved in their children’s learning, particularly in mathematics. By addressing this recommendation, teachers, parents, and students will know the underlying causes that hinder achievement in mathematics