Behind every good leader is a great support system. In schools, that support system often begins with the assistant principal (AP) role.
A new report from Mathematica, Vanderbilt University, and Policy Studies Associates, supported by The Wallace Foundation, takes a deep dive into the AP role, highlighting how it is growing in numbers and importance. In fact, two-thirds of U.S. public schools now have one or more assistant principals, a rise from just 34 percent three decades ago. The report draws on a fall 2024 RAND survey of 1,019 principals, a nationally representative sample of K-12 public schools.
Here are the main takeaways.
The Role Keeps Growing
In 1990-91, only 34 percent of public schools had at least one assistant principal. By 2020-21 that figure was 61 percent, and in 2024-25 it reached 67 percent. Schools with multiple assistant principals are also becoming more common, rising from 11 percent in 1990-91 to 21 percent in 2020-21 and 25 percent today. Researchers believe that suggests schools are adding leadership roles such as the AP to handle the more complex demands they face.
In addition, the ratio of students to assistant principals has narrowed over time. In schools with an AP, the average number of APs is 1 for every 433 students, compared to 1 for every 531 students in 1990.
APs Are Most Common in Three Types of Schools
The study found that assistant principals are most prevalent in:
- Middle and high schools, where more than 80 percent have at least one
- Urban schools, where 77 percent have one, compared with 71 percent of suburban schools
- Schools serving mostly students of color, where 79 percent have one
Researchers noted that these trends were likely due to states and districts “allocating more assistant principals to schools that serve higher grades, larger student populations, and higher levels of student need.” Title I schools were slightly more likely to have an AP than non-Title I schools (68 versus 65 percent). The use of Title I and other funds to hire assistant principals to address student needs may also help explain “the higher prevalence of assistant principals at schools that serve students with greater needs, such as multilingual language learners and students experiencing poverty.”
APs Spend Most of Their Time on Discipline and Instructional Leadership
According to principals, who were the ones surveyed, their assistant principals spend an average of 29 percent of time on student discipline and 25 percent on instructional leadership—planning with teachers, coaching, and observing classrooms. The rest of their time is spread across non-disciplinary student support, parent engagement, supervision duties like lunch and bus duty, and administrative work like hiring and budgeting.
However, there were some dramatic variations within those averages. For example, some principals reported their AP spent up to 90 percent of their time on discipline, while others reported up to 75 percent on instructional leadership. Instructional leadership took up more time in urban and suburban schools, Title I schools, and large districts. Experience mattered little: novice and veteran APs spent their time in similar ways.
When schools have more than one AP, principals typically divide the work by grade level or by task. High school assistant principals were more likely to have their responsibilities divided up by task, such as discipline, instruction, or athletics.
Support Is Common but Uneven
The study concluded that most assistant principals get some professional development and support, but there are gaps:
- Mentoring and coaching: 63 percent of principals said their APs had access to a program, but 37 percent said they had none. Middle school APs had the least access (52 percent), while APs in large districts had the most (75 percent).
- Principal check-ins: 87 percent of principals meet with their AP at least weekly, and 27 percent of those meet daily.
- Professional development: The most common formats reported were leadership programs (62 percent), assistant principal networks (56 percent), and workshops or conferences (55 percent).
- Evaluation: 82 percent of principals said their district evaluates APs with the same system used for principals, which previous research suggests may not fit the AP role well.
When asked to rank the top professional development needs for their APs, principals most often named leadership skills such as strategic planning and teamwork (44 percent) and using data for school improvement (43 percent). About 30 percent cited observation and feedback for teachers and general preparation for the principalship.
Assistant Principals Are Prepared for the Principalship
Principals surveyed seemed to have great confidence in their APs taking on the principalship role. About Sixty-nine percent said at least some of their assistant principals were prepared to become principals. This confidence was greater depending on the APs’ experience: 60 percent of principals with a novice AP (two or fewer years) said they were ready to be principals, compared with 80 percent of those with a more experienced AP. High school principals (80 percent) were more positive than middle school (70 percent) and elementary school (63 percent) principals.
Guidelines for District Leaders
Based on these findings, the authors offer four recommendations for strengthening the assistant principal role:
- Develop the AP role to strengthen teaching, learning, and student support, not just management and oversight. Make sure their skillset is broad and addresses the wide range of roles needed for school leadership.
- Align AP responsibilities with both school needs and APs’ career goals, including intentional chances to practice instructional leadership and other principal-level tasks.
- Strengthen access to professional development in the areas of greatest need, especially leadership skills and data use, with a preference for programs with evidence of effectiveness.
- Support principals as mentors through their own training and better align evaluation systems with the AP role so they can provide useful developmental feedback.
Supporting the Assistant Principal
The assistant principalship is a vital—and growing—position in schools. Yet the role’s definition, support, and evaluation haven’t kept pace with its growth. As schools rely on APs to manage discipline, coach teachers, and prepare to be the next generation of principals, districts need to be as intentional about developing these leaders as they have been about hiring them.
To learn more, read the full report here.
