This study aimed to explore teachers' perceptions of the "dominant gender" phenomenon and its impact on instruction and classroom management in mixed-gender schools in Kabudarahang. The research employed a descriptive phenomenological approach. Data were collected through semi-structured interviews with 13 purposively selected teachers and analyzed using Colaizzi’s seven-step strategy via MAXQDA software. For trustworthiness, Guba and Lincoln's four criteria—credibility, transferability, dependability, and confirmability—were applied. Findings revealed that despite challenges such as gender-based conflicts, mixed-gender classrooms provide opportunities for social maturity and the exchange of learning strategies. Male predominance shifts the classroom focus toward practical and athletic activities, yet complicates management and may marginalize female students. Conversely, female predominance enhances discipline, hygiene, and achievement in arts-related subjects, though it entails challenges like constant verbal interactions and classroom noise. Furthermore, teachers' preferences for a specific dominant gender are influenced by their personal inclinations and perceptions, such as the rapid learning of boys versus the perseverance of girls. Ultimately, the dominant gender shapes the "learning atmosphere," and teachers' perceptions of this dynamic significantly influence instructional choices and the extent of attention given to the minority gender's needs.