Objective To analyze the current status of occupational stress among primary and secondary school teachers, and explore the dose-response relationship between weekly work hours and occupational stress. Methods A total of 1 252 teachers from 13 primary and secondary schools in three prefecture-level cities of a central province of China were selected as the research subjects by the convenience sampling method. The Core Occupational Stress Scale was used to assess occupational stress levels of the teachers. Multivariate logistic regression analysis combined with restricted cubic spline models was applied to study the dose-response relationship between weekly work hours and occupational stress. Results The average weekly work hours were (55.3±15.9) hours, with 78.6% of teachers working more than 40.0 hours per week. The total score of occupational stress was (40.3±8.2) points, and the detection rate of occupational stress was 29.8%. Multivariate logistic regression analysis combined with restricted cubic spline models revealed a linear dose-response relationship in weekly work hours and occupational stress among teachers (P for overall trend <0.05, P for nonlinearity was 0.22). Result of age-stratified analysis showed that weekly work hours had a linear dose-response relationship with occupational stress risk in teachers aged 21-<31 and 31-<46 years (P for overall trend <0.05, P for nonlinearity was 0.71 and 0.27, respectively). However, no association was found between weekly work hours and occupational stress risk among teachers aged ≥46 years (P for overall trend =0.08, P for nonlinearity was 0.09). Conclusion There is a linear dose-response relationship between weekly work hours and occupational stress among primary and secondary school teachers in the province, with younger teachers being more susceptible to suffer occupational stress due to long working hours.