This study investigated Teacher Effectiveness Through Healthy School Environment in Nigeria. Healthy School Environment is said to be one of the most efficient strategies that a nation might use to prevent major health and social problems with the aim of improving teacher education to boost teaching and learning in schools. The instrument used to elicit information was a questionnaire designed by the researchers titled Teacher Effectiveness Through Healthy School Environment in Nigeria Questionnaire. The descriptive research design of the survey type was used for the study. The population of the study was all the teachers in Nigeria Secondary Schools. From this, a sample of four hundred and three teachers were selected using simple random sampling technique. Two research questions were raised and two hypotheses were formulated. The data collected were analysed using percentages, frequency counts and chi-square. The result of the analyses showed that water and sanitation are vital issues in improving teacher effectiveness. The result also show that security measures and safety of learners helps in the improvement of teaching and learning by ensuring punctuality, regularity in school attendance. Finally, nutrition helps learner to concentrate in the class. It was therefore concluded that government should ensure that regular washing of hands, drinking of clean water, punctuality and regularity in school attendance be considered as vital in the improvement of Teacher Effectiveness in Nigeria schools to enable optimal performance of the teachers in ensuring effective teaching and learning in the schools. Keywords : Teacher Effectiveness, School Environment, Nigeria DOI: 10.7176/JEP/12-3-22 Publication date: January 31 st 2021