It has been observed that teachers, particularly junior ones, in public secondary schools do not perform their instructional and non-instructional tasks satisfactorily. This could be as a result of inadequate exposure to in-service training and lack of mentoring by principals and senior teachers in the teaching profession. This study therefore examined in-service programmes and mentoring as determinants of teachers’ job performance in public secondary schools in Ondo Senatorial District, Nigeria. The descriptive research of the survey type was adopted. The sample consisted of 324 respondents that were selected using multistage procedure. Two questionnaire instruments entitled “In-service Training and Mentoring Strategies Questionnaire (ITMSQ)” and “Teachers’ Job Performance Questionnaire (TJPQ)” were used for data collection. Two research questions were raised and answered using frequency count, percentage and mean while two hypotheses were formulated and tested using Pearson Product Moment Correlation at 0.05 alpha levels. Findings revealed that that teachers perceived in-service training as a tool that moderately improve teachers’ capacity; there was a significant relationship between in-service programmes and teachers’ job performance; and a significant relationship existed between mentoring strategy and teachers’ job performance. Based on the finding, it was concluded that both in-service and mentoring strategies contribute positively to teachers’ job performance in public secondary schools. It was recommended, among others, that Government should encourage teachers to access capacity training within and outside the school by giving monetary assistance and due recognition to participants.Keywords:
In-service training programmes, mentoring, teachers’ job performance, public secondary schools.