Background: Childhood myopia is a global health concern, with high prevalence in East Asia. Risky eye behaviors fuel myopia, but how combined parental and teacher supervision affects these behaviors remains poorly understood. Methods: This cross-sectional study surveyed 5193 participants in 8 schools. Indicator variables of parent-teacher supervision were divided into three levels. Student eye behaviors were defined as myopia-risk behaviors. K-means clustering and binary logistic regression analyzed the relationship between supervised level and eye behaviors. Results: Among the 5193 participants, the number of high, medium, and low supervision groups was 3204 (61.7%), 1165 (22.4%), and 824 (15.9%), respectively. Compared with the high-level group, the medium-level and low-level groups had higher risks of lying down to read books or using electronic devices in the dark, and lower risks of sitting upright while studying. Implications for School Health Policy, Practice, and Equity: Findings highlight the need for school health policies promoting collaborative parent-teacher supervision, tailored practices to reduce risky eye behaviors, and equitable interventions to address supervision disparities. Conclusions: Supervision by parents and teachers may reduce students' risk of unhealthy eye behaviors. This provides beneficial strategies for preventing myopia among students.