Objectives: The coronavirus disease 2019 (COVID-19) pandemic developed rapidly, with changing guidelines, misinformation, inaccurate health information and rumors. This situation has highlighted the importance of health literacy, especially among educators. The aims of this study were (i) to assess COVID-19-specific health literacy among school teachers in Hong Kong and (ii) to examine its association with demographic factors, self-endangering work behaviors (i.e., work intensification, work extensification and work quality reduction), secondary burnout symptoms (i.e., exhaustion related to work and psychosomatic complaints), the level of knowledge of COVID-19- or pandemic-related information and the level of confusion about COVID-19-related information. Methods: A self-report survey was administered to 366 Hong Kong school teachers from April 2021 to February 2022. COVID-19-specific health literacy was measured using the HLS-COVID-Q22 instrument. Other instruments, including self-endangering work behavior scales (i.e., extensification of work, intensification of work and work quality reduction) and two dimensions of the Burnout Assessment Tool (i.e., psychosomatic complaints and exhaustion) were also used for assessment. Data were analyzed using an independent samples Student's t-test, analysis of variance, correlation analysis and adjusted multilinear regression models. Results: The results showed that 50.8% of school teachers had sufficient health literacy, 38.3% had problematic health literacy and 10.9% had inadequate health literacy. The HLS-COVID score did not vary by sex, but varied according to the type of school, the number of working hours per week and the number of students attending the school. Teachers with sufficient health literacy scored significantly lower for two types of self-endangering work behavior–intensification of work (p = 0.003) and work quality reduction (p = 0.007)—than those with insufficient health literacy. After excluding those who had already been vaccinated, respondents with sufficient health literacy felt more positive about COVID-19 vaccination than those with insufficient health literacy (t[180] = 4.168, p < 0.001). In addition, teachers with sufficient health literacy felt more informed (p < 0.001) and less confused (p < 0.001) about COVID-19-related information than those with insufficient health literacy. Multiple linear regression analysis revealed that age (β = 0.14, p = 0.011) and the number of teaching hours per week (β = −0.206, p < 0.001) were significant predictors of the HLS-COVID score. Conclusions: The findings of this study may serve as a guide for addressing health literacy gaps among school teachers.