There is a need to investigate the effects of supervision practices of school principals on teachers' work performance and growth in Pakistani society. Hence, this study aimed to investigate the supervision practices of school managers related to staff development and its relationship with teachers' work performance and growth in primary schools. To achieve this objective, this study collected data through survey instrument from a sample of principals and teachers in Lahore, Pakistan. The results, obtained from correlation and regression analyses, revealed that supervision practices of principals related to staff development are indeed helpful in attaining better performance of teachers and their overall growth. Further, it was also found that there is not much difference between staff development practices of male and female school principals. On the other hand, the results of data analysis also found significant difference between work performance and growth of male and female school teachers. The study concluded that enhancement and polishing of principals' staff development supervision practices is of utmost importance as it significantly contributes towards the improvement in work performance and growth of school teachers.