The study ascertained principals' application of management support practices for enhancing teachers' job performance in secondary schools in Enugu State. Two specific purposes were formulated and two research questions guided the study. Descriptive survey design was adopted for the study. The target population of the study comprised all the 291 principals in public secondary schools in Enugu State. Simple random sampling technique was used to sample 146 principals for the study. A 13 items researcher developed instrument titled; Principals' Application of Management Support Practices Questionnaire (PAMSPQ) was used for data collection. The instrument was face validated by three research experts. The Cronbach alpha was used to determine the reliability of the instrument which yielded a high reliability coefficient value of 0.77. Data analysis was done using mean and standard deviation. The findings revealed among others that principals do not apply professional development practices for enhancing teachers' job performance by not; involving teachers in collaborative teaching method to enable them share knowledge and new teaching strategies, sponsoring teachers' on conferences to enable them withstand the challenges brought about by change and innovation, and granting study leave for teachers to go for refresher courses. Hence, it was recommended among others that principals should partner with relevant stakeholders to promote teachers professional development through organizing annually seminars, workshops, sponsoring teachers on conferences and embarking on continuous training so as to improve teachers instructional delivery. Conclusion was drawn based on the findings.