The aims of this study describes and analyzes the contributions: organizational commitment to the quality of learning; school-based lesson study (SBLS) on the quality of learning; an organizational commitment to professionalism; SBLS towards professionalism; professionalism towards the quality of learning; an organizational commitment to the quality of learning through professionalism; and SBLS on the quality of learning through professionalism. This research used a quantitative method by distributing questionnaires with a Likert scale. The study population was 128 teachers with a sample of 97 teachers who were selected by proportional random sampling at State Middle Schools in Banjarbaru City-collecting data using instruments that have been valid and reliable. Data were analyzed descriptively and path analysis. The research results show: (1) organizational commitment has a contribution to the quality of learning, (2) SBLS has a contribution to the quality of learning, (3) organizational commitment has a contribution to professionalism, (4) SBLS has a contribution to professionalism, (5)) professionalism has a contribution to the quality of learning, (6) organizational commitment has a significant indirect contribution to the quality of learning through professionalism, and (7) SBLS does not have an indirect contribution to the quality of learning through professionalism.