With the quantitative and G-theory methodologies, this study investigated the perceptions of assistant principals in the states of Pennsylvania and Texas about their evolving roles and responsibilities. The research results suggest there was consistency in terms of the importance of the 56 school activities to the success of schools in teaching and learning as rated by assistant principals. Most of the 56 activities were considered important to teaching and learning by assistant principals regardless of their gender, age, years in present position, and years of experience in education, although there was still some unexplained variability in each assistant principal's rater group.