School Learning Action Cell (SLAC) is a school-based professional learning community designed for the development of teachers, mandated by the Department of Education (DepEd) in the Philippines. This study sought to evaluate the level of SLAC implementation and its impact on the professional development of Araling Panlipunan teachers in Sto. Niño District, Sto. Niño, South Cotabato. A descriptive and correlational research design was used in this study, and 34 Proficient (Teacher I- III) secondary Araling Panlipunan teachers were considered respondents. Due to their limited number, the total enumeration sampling technique was used to select the teacher-respondents. Frequency, percentage, mean, standard deviation, Pearson r moment correlation and One- way Analysis of Variance (ANOVA), t-test, and Tukey- Kramer Multiple Comparison tests were used to analyze the data. Findings revealed that The SLAC is fully implemented in secondary schools in the district in terms of content and pedagogy, content assessment, ICT integration and 21st century skills and curriculum contextualization with no significant difference in the level of implementation. Furthermore, SLAC had a very strong impact on the Professional Development of Araling Panlipunan teachers in terms of pedagogical, personal, social, and professional competence. The impact of SLAC implementation on the Personal Competence of teachers is slightly lower yet remains highly significant. Moreover, the level of SLAC implementation has a strong relationship with the professional development of Araling Panlipunan teachers. The age, the teaching experience, and the classroom observation ratings of the respondents also had a significant influence on the professional development and SLAC implementation.