Even though Social and Emotional Learning (SEL) has become a central domain in education, there is still a lack of clarity in the underlying conceptual models guiding educational efforts and insufficient empirical evidence supporting these models. The Chilean Agency for Quality in Education developed a socioemotional questionnaire as part of the Comprehensive Learning Diagnosis (DIA), administered in educational institutions nationwide. Its underlying conceptual model considers nine SEL competencies structured into three dimensions: Individual, Communal, and Civic, mapping onto the Chilean educational curriculum and learning goals relative to SEL. Even though this model was built based on a thorough revision of existing approaches to SEL and assessment tools, this dimensional structure has not been empirically tested. This study explores a dimensional model of SEL based on a large‐scale sample of Chilean students assessed through the DIA (882,553 7th–12th graders). Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were conducted to determine the dimensional structure, also testing for invariance by educational level (basic vs. secondary education) and gender. EFA evidenced a three‐dimensional structure, with factors labeled as individual, relational, and socio‐moral based on their composition. CFA confirmed these dimensions with adequate fit indices. Factorial invariance of the identified model was found between basic and secondary school students, and between boys and girls. The study allowed for the construction of a theoretical model of SEL based on a large‐scale sample. The identification of a moral factor as a key dimension of SEL constitutes a novel and promising perspective, in line with recent research providing new insights into SEL. Further evidence regarding the reliability and validity of the instrument should be analyzed. Also, the proposed SEL model should be tested in different countries and populations to broaden our understanding of SEL and inform educational policies and practices.