Abstract: This study purposed to evaluate the relationship between principals’ supporting professional development strategy and teachers’ job performance in public secondary schools in Ondo West Local Government, Nigeria. The study was guided by Social Exchange Theory. This study employed convergent parallel mixed-methods design. The target population was the 32 public schools in Ondo West Local Government. Ten (10) schools were selected through stratified random sampling. All the 10 principals of the sampled schools were included in the study. Yamene (1967) formula was used to sample of 211 teachers. Questionnaire was used to collect data from the teachers, while interview guide was used to collect data from the principals. In the analysis of quantitative data, descriptive analysis was employed and findings were reported in percentages, frequency tables, pie charts, and graphs. The qualitative data was thematically analyzed and presented in forms of narratives and direct quotations. The study’s findings established that professional development strategy positively influence teachers’ job performance in public secondary schools in Ondo West Local Government. Majority of the teachers (68%) agreed that principals provide and support on going on-the-job training activities for teachers. However, minority of teachers (29%) expressed disagreement to the statement while 3% of the teachers were not sure about the statement. In order to improve on sub-optimal performance of teachers, the study recommended that principals should engage teachers more in decision making processes, align professional development to the needs of the teachers’, principals be consistent and fair in their motivation strategy, and encouraging collaboration among teachers in the public schools in Ondo West Local Government. 

Key words: Principals’ supporting professional development strategy, teachers’ performance, public secondary schools