Objectives: Children spend the daytime participating in classes and sports. Hence, as the general caregiver of children during school hours, the teacher has a role in managing those with asthma. The present study aims to identify teachers’ knowledge, attitude, and experiences about childhood asthma in primary and secondary schools in Ilorin, Nigeria. Materials and Methods: A cross-sectional study was conducted among 1532 teachers from 64 schools (24 primary and 40 secondaries) selected through multistage sampling. A 40-item Asthma Knowledge Questionnaire was used to assess teachers’ knowledge about childhood asthma. A score of <22 out of 40 was considered suboptimal knowledge of childhood asthma. Results: The response rate was 92.8%. Two-thirds of respondents were female. The overall mean age was 33.8 ± 8.1 years. The median (interquartile range [IQR]) teaching duration was 6 (3–11) years. The teachers had the highest median score (60.0%) in the triggers domain and the lowest median score (33.3%) in the symptoms domain. The overall median (IQR) knowledge score of the primary school teachers was 50.0 (30.0–65.0%), and for the secondary school teachers was 52.5 (30.0–65.0%), P = 0.689. Two hundred and ninety-one (55.1%) primary teachers and 479 (53.6%) secondary teachers had suboptimal knowledge. Teachers with an asthmatic relative, an asthmatic child in the class, or who previously witnessed a child with an asthmatic attack had – significantly better asthma knowledge, with each P < 0.05. Conclusion: About half of the teachers surveyed had suboptimal knowledge of asthma. Strategies to improve teachers’ knowledge are crucial for improved childhood asthma management in Ilorin schools.