This study examines whether Superintendent-Principal Partnership Longevity has a relationship with student Annual Graduation Rates in New York State from 2009 to 2018. Previous research has explored the role of individual school leadership longevity (superintendent or principal) on student achievement. Superintendent-Principal Partnership Longevity, defined as the number of consecutive years a superintendent and principal work together, has not previously been investigated to examine its relationship to student achievement in schools. This study employs an archival, quantitative, correlational methodology to examine the relationship, if any, between the Superintendent-Principal Partnership Longevity and high school Annual Graduation Rates while controlling for student and school demographics in New York State from 2009 to 2018. The study examines Annual Graduation Rates across demographic subgroups within 704 public high schools within New York State over 10 years, excluding New York City and charter schools. The research findings revealed that Annual Graduation Rates across New York State increased in the 10-year study, except for English Language Learners. The average Superintendent-Principal Partnership Longevity reached approximately 3.7 years for all Need/Resource Capacities studied except Large City districts. In conclusion, the study found that the Superintendent-Principal Partnership Longevity does have a very weak statistically significant relationship with Annual Graduation Rates, though it varies across school Need/Resource Capacity and demographic subgroups. The implications for school policy, practice, and future research are discussed. [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/en-US/products/dissertations/individuals.shtml.]