New Research on a Rapidly Growing But Understudied K-12 Leadership Role

Assistant Principals: Growth and Implications for School Leadership

This report documents the proliferation of assistant principals in public schools–where they work, what they do, and what additional support they need.

A new report documents the dramatic growth of assistant principals in public schools over the past three decades. It provides rare insights on their day-to-day roles, whether they get the on-the-job learning opportunities they need to rise in the ranks, and how they are assigned.

The Mathematica study, based on nationally representative survey data, shows that two thirds of public schools had at least one assistant principal during the 2024-25, a dramatic upswing from 34 percent in 1990-91. Assistant principals are most common in middle and high schools, urban schools, and those with a high percentage of students of color. Typically, they focus mainly on student discipline and instructional leadership.

“Continued growth in the number of assistant principals reinforces the importance of the role in supporting principals and strengthening schools,” the report says. “Assistant principals are especially critical in not just management and oversight duties, but also instructional leadership and support of high-need schools and students.”

Most assistant principals have access to mentoring and participate in various professional development activities, the report says. With that said, they need more support with leadership skills, using data for school improvement, and providing instructional leadership. Two out of three principals report that at least some of their assistant principals are ready to take the helm of a school.

The report identifies strategies that policymakers and district leaders can employ to help support assistant principals, including:

Ensure their roles align with their career aspirations and the school’s needs
Strengthen professional development on topics of highest need for assistant principals
Help principals themselves to more effectively mentor and develop the assistant principals they supervise

A forthcoming report, also supported by Wallace, will delve deeper into the assistant principal role in three large urban districts to describe findings on assistant principals’ diversity, responsibilities, support, and career paths. Together, these reports will help build evidence about assistant principals, identify opportunities to better support them in their current roles, and more effectively prepare them to become principals.