Background: School Health Profiles assesses school health policies and practices among US secondary schools. Methods: The 2020 School Health Profiles principal and teacher questionnaires were used for a test-retest reliability study. Cohen's kappa coefficients tested the agreement in dichotomous responses to each questionnaire variable at 2 time points. The aggregate prevalence estimates between time 1 and time 2 were compared for each questionnaire item via overlapping 95% confidence intervals. Chi-square tests examined whether the prevalence at time 2 differed between paper and web administration for both questionnaires. Results: For the principal (N = 50) and teacher (N = 34) data, there were no significant differences in the prevalence of any items between time 1 and time 2. For the principal survey, the mean kappa for 191 variables was 0.49. For the teacher survey, the mean kappa for 260 variables was 0.65. Overall, 60.7% of principal and 91.1% of teacher questionnaire items had at least "moderate" reliability. Conclusions: School Health Profiles offers education and health agencies a reliable tool to monitor school policies and practices.