This study explores the impact of teacher self-efficacy on their enthusiasm for implementing differentiated instruction in primary schools. Teacher self-efficacy, defined as a teacher’s belief in their ability to effectively manage and teach diverse learners, has been identified as a crucial factor in enhancing teaching quality and job motivation. The research was conducted with a sample of 200 primary school teachers selected through stratified random sampling from both public and private schools. The study employed a quantitative research design, utilizing surveys to measure teacher self-efficacy and their enthusiasm for differentiated teaching methods. The findings indicate a significant positive correlation between teacher self-efficacy and their enthusiasm for differentiated instruction. Teachers with higher levels of self-efficacy were more inclined to adopt differentiated teaching methods, which, in turn, was associated with improved student outcomes. Furthermore, the study reveals that teachers’ self-efficacy significantly influences their ability to manage classroom behaviors and apply diverse instructional strategies. The results also show that female teachers and those in private schools were more enthusiastic about using differentiated instruction compared to males and public-school teachers. These findings highlight the importance of fostering teacher self-efficacy as a means to enhance the effectiveness of differentiated instruction and improve job satisfaction.