This study is aimed at investigating the impact of staff development programmes on the instructional task performance of secondary school teachers in Kaduna metropolis. Five objectives were generated alongside with five research questions. The study was limited to principals and teachers in private and public secondary schools in Kaduna metropolis. The literature review comprehensively discussed issues that form the objectives of the study (in-service, seminar, conferences, workshop and mentoring). The research design adopted was survey method. Thirty-eight (38) government secondary school and ninety-four (94) registered private secondary schools making a total of one hundred and thirty-two (132) forms the population of the study. Stratified random sampling was adopted to arrive at twelve government secondary schools and sixteen private secondary schools. The total numbers of sampled respondents were four hundred (400). The research instrument used for data collection was a five-likert scale questionnaire containing section A (bio-data of respondents) and section B (item statements generated from issues that form the objectives of the study). The research instrument was validated by experts in the field of educational administration and planning, a pilot study was carried out and the reliability coefficient of 0.77 was established. The data collected were analyzed using frequency tables, percentages and standard error. The results were tabulated and discussed. The following major findings were established; in-service has both intrinsic and extrinsic benefits to teachers, seminar programs give teachers the opportunity to fulfil their potentials by learning new skills, and generally improve their instructional effectiveness and quality of service through improved performance. The researcher concluded that there is a positive correlation between staff development programs and the instructional task performance of secondary school teachers, staff development help teachers create the understanding from experiences with peers and resources and reflect upon those experiences. The researcher stated the following recommendations; policy makers and administrators should revise staff development program policy, staff development programs should be organized periodically and academic mentors should be employed by administrators to help novice teachers become successful in their teaching profession.