This study aimed to determine the reflections on the least learned competencies in Mathematics of Grade 10 students of Jupi National High School for school year 2020 – 2021. The participants of the study were 20 Grade 10 students. Mixed method of research was utilized as research design of the study. Quantitative method for the academic performance using summative tests while qualitative method for the reflections of the students were their responses were gathered using interview guide. The study revealed that students performed very satisfactorily in permutation and combination. However, they performed satisfactorily in coordinate proof, equation of circle, and problems involving circle. The overall performance Grade 10 students was very satisfactorily because of the mean performance is 84.92. The least learned competencies of the students as revealed by their reflections the selected topics in mathematics were solving problems along permutation, combination, and circles, proving theorems, finding the equation, and plotting of points and graphing of circles. This study also revealed Student-related factors, home related factors and subject-related factors which hampered in their learning the competencies in Mathematics. A lesson plan exemplar was developed in order to address the least learned competencies by the students in Mathematics.