Self-concept in mathematics can be defined as student ratings of their skills, ability, enjoyment, and interest in mathematics is seen as an essential factor in their achievement in math. This study assessed the self-concept and academic performance in Math of the Grade 10 students of a public national high school, Cebu, Philippines. The study employed descriptive correlational research. One hundred eighty-three respondents were asked to answer a survey questionnaire in order to measure their self-concept. Their academic performances were assessed using their grades in Math. The assembled information was dealt with measurably utilizing recurrence, percentage, weighted mean, t-test, and Pearson r. Results revealed that they had a moderate level of self-concept towards learning Mathematics. No gender difference was found on the self-concept of the respondents, but there was a significant relationship between self-concept and the respondents' academic performance in Mathematics. Hence, a Math performance enhancement plan is highly recommended for adoption and evaluation.