At the time I conducted this research study, the Puerto Rico public school system did not include an AP position in their school leadership structure. Using quantitative descriptive statistics research, I conducted this study to assess the knowledge and perceptions of PR school principals regarding adding an assistant principal (AP) position into the PR public school system. I chose a Distributed Leadership Practice (Spillane, 2006) theoretical framework as the lens for the study. In the research study, I measured the willingness of school principals to delegate or distribute certain administrative, managerial, and instructional leadership duties to an AP. For the literature review, I investigated three primary factors described in a conceptual framework: (1) The School Principal Role and Responsibilities, (2) The School Assistant Principal Role and Responsibilities, and (3) The Puerto Rico School System's History and Evolution. The literature review revealed that the AP position could serve as a training field for principals, and that APs are a resourceful support to school principals (Barnett et al., 2012; Oliver, 2005). The study had two primary research questions: (1) What are the perceptions of serving principals in Puerto Rico regarding the potential role and responsibilities of an assistant principal? (2) What is the degree of understanding and knowledge of serving principals in Puerto Rico regarding the roles and responsibilities of an assistant principal? For data collection, I used an electronic survey sent to a population of 1,292 school principals in public schools, with 486 responses at a 37.6% response rate. I designed the 24 question survey with demographic, Likert scale, and open-ended questions. The data results revealed a statistically significant rate of support (52.1%) for delegating a portion of the principals' administrative and instructional leadership duties to an assistant principal. The study's results answered the research questions. The findings supported adding the AP position into the PR school system using a leadership practice model (Spillane, 2006). School principals named three primary responsibilities AP's could share: administrative responsibilities, support with instructional leadership, and student discipline. In addition, findings revealed females more inclined to delegate instructional leadership than males and that principals with more years of service in the PR school system supported adding an AP position into the PR school leadership structure. In a challenging school environment, the assistant school principal becomes an asset for the school principal, if there is synergy and coupling of vision for change and improvement shared by both school leaders (Morgan, 2018). [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]