Abstract: This study investigated the impact of teacher professional development programs on student learning outcomes in tertiary institutions within Lagos State, Nigeria. A descriptive research design was employed to explore the relationship between these variables. Five tertiary institutions were purposefully selected, with a sample of 250 participants (200 students and 50 lecturers) randomly chosen from each. Data was collected using the Teacher Professional Development Programme and Student Learning Outcome Questionnaire (TPDPSLOQ), a validated instrument with a Cronbach’s Alpha reliability coefficient of 0.791. Descriptive statistics and Chi-square analysis were used to examine the data. Findings revealed a moderate implementation of teacher professional development programs and a significant positive impact on student learning outcomes. Furthermore, the study indicated that different types of professional development programs varied in their effectiveness on student learning. This research underscores the importance of well-designed and implemented professional development programs in enhancing tertiary education. The research concludes that while teacher professional development programs have a positive impact on student learning, optimizing their effectiveness requires further exploration and targeted interventions. The study recommends that there is need to conduct a comprehensive evaluation of the current teacher professional development programmes in tertiary institutions in Lagos State to determine areas of improvement and to identify best practices that can be replicated. Also, the researcher recommended that there is need to implement a variety of teacher professional development programmes, including workshops, seminars, online courses, and mentoring programs, to cater to different learning styles and preferences of educators in tertiary institutions.

Keywords: Effectiveness, Students, learning outcome, professional development programmes and tertiary institutions.