This study investigates the determinants of mathematics self-efficacy (MSE) among Brazilian high school students using a mixed-methods design grounded in Social Cognitive Theory and the KAPA model. A total of 833 students from public schools completed validated self-efficacy scales and responded to open-ended questions about their perceived strengths and weaknesses in mathematics learning. Quantitative analyses indicated that reading–writing self-efficacy, self-regulated learning, and emotional self-efficacy were significant positive predictors of MSE, while prior academic failure negatively influenced students’ beliefs. Gender differences were also observed, with male students reporting higher MSE. Qualitative findings revealed that students primarily attribute success in mathematics to cognitive skills and focus, whereas difficulties are associated with concentration problems, content comprehension, and emotional factors such as anxiety. The integration of datasets demonstrated that MSE is shaped by a dynamic interplay between cognitive, emotional, and experiential factors, consistent with KAPA’s distinction between knowledge and appraisal processes. The findings highlight the importance of multidimensional and context-sensitive interventions aimed at strengthening students’ self-efficacy, through the development of literacy, self-regulation, and emotional competencies, contributing to improved mathematics learning outcomes.

Roberto Iaochite is an associate Professor in the Department of Education at Sao Paulo State University (UNESP), Rio Claro campus. Holds a degree in Physical Education and a Master’s in Sciences of Motricity from UNESP, a PhD in Education from UNICAMP, and a postdoctoral degree in Psychology from São Francisco University. Conducts research grounded in Social Cognitive Theory, with an emphasis on teacher and academic self-efficacy, teacher education processes, and health-promoting schools. Leads the Research Group on Social Cognitive Theory and Educational Practices, contributing to human resource development at undergraduate and graduate levels through supervision and research projects. Participates in national and international research networks, collaborating with multiple institutions and engaging in interinstitutional projects. Has experience as a visiting researcher at international universities and is actively involved in academic management and scientific editorial activities, contributing to the advancement of knowledge in Education.