The current study explores the differential relationship between social and emotional learning (SEL), based on the Big Five personality traits, and mathematics achievement among Turkish high school students. Using data from the OECD's 2019 Survey on Social and Emotional Skills (SSES), it examines how SEL dimensions predict math outcomes and how these relationships vary by gender, socioeconomic status (SES), and level of SEL evaluation in schools. Key findings reveal that open-mindedness and emotional regulation positively correlate with math achievement, while high social engagement shows a negative association. Girls' SEL skills had a stronger predictive value for math achievement than boys, and SEL had a more substantial impact on students from lower SES backgrounds. Formal SEL assessment in schools was also related to higher math scores. These results emphasize the importance of SEL programs tailored to specific demographic needs, particularly for disadvantaged students, and suggest that formal SEL assessment in schools could enhance academic outcomes.