Employment figures and population demographics indicate that Baby Boomers (1946-1964) hold a small and shrinking share of school principalships. The oldest Baby Boomer principals began to retire during the middle of the 1990s, and their void created an opportunity for younger Baby Boomers and members of Generation X (1965-1981) to replace them. The youngest Baby Boomer principals are beginning to retire, and Millennial Generation (1982-2000) administrators are stepping up to fill the ranks. Millennial Generation educators have been in the field long enough to develop the requisite classroom teaching experience, graduate school master's level education, and training needed to obtain administrative positions. Principals develop their leadership skills through the assistant principal experience, and because Millennials are a relatively new addition to the ranks of assistant principals, little is known about their perceptions' of the challenges and rewards of the principalship. Generational differences between Generation Xers and Baby Boomers have been investigated by other researchers, but this study was unique because it directly compared Generation X and Millennial Generation assistant principals. The study explored Generation X and Millennial Generation assistant principals' perceptions of the challenges and rewards of the principalship. This qualitative study involved 12 assistant principal participants, and the analysis of the coded interview transcript data produced major coded themes with valuable implications regarding the participants' motivations, career ambitions, professional development needs, and their perceptions' of the principalship. This study indicated that Generation X and Millennial Generation assistant principals have distinct similarities and differences, and school division superintendents who understand the generational differences may make more informed leadership and personnel decisions about their future principals. The findings and implications were intended to assist superintendents and personnel/human resource directors in their efforts to recruit, select, support, and ultimately promote Generation X and Millennial Generation assistant principals to the principalship. The findings of this study suggested opportunities for researchers to continue the investigation of the topic. / Ed. D.