This qualitative study explores the implementation of reinforcement strategies by English teachers at SMP N 1 Ajibarang. The research investigates the types of reinforcement employed and the principles guiding their application in the classroom. Data was collected through classroom observations across grades 7, 8, and 9, in-depth interviews with all English teachers, and interviews with two students from each grade level. Supplementary documentation was also analyzed. Thematic analysis, involving data reduction, data display, and conclusion drawing, was used to interpret the collected data. The findings reveal that English teachers utilize a variety of reinforcement types, including positive reinforcement, negative reinforcement, and punishment. The implementation of these reinforcements is further characterized by adherence to key principles such as warmth and enthusiasm, fairness, diversity, balance, and meaningfulness. This study provides insights into the practical application of reinforcement theory in a junior high school English language learning environment.