Historically, P-12 schools and institutions of higher education have operated independently of each other, creating a gap that acts as a barrier between high school and postsecondary institutions. This gap is blamed for many societal issues including high college remediation rates, low college-going rates among minority groups, and low six-year college graduation rates. P-20 partnerships, agreements between P-12 schools and institutions of higher education with the purpose of improving the P-20 education system, have emerged as a way to address these problems. From laboratory schools in the 19th century to modern-day professional development schools, P-20 partnerships in teacher education have been well-documented. However, analysis of P-20 partnerships outside teacher education is lacking. This research augments the current literature by examining three exemplary P-20 partnerships outside teacher education to explore how they define and measure success and what resources they perceive to be essential to their success. These topics were investigated using a mixed methods approach from the perspective of three distinct groups: state-level leaders in P-12 and higher education, P-20 partnership leaders, and P-20 partnership participants. While P-20 partnerships have diverse purposes, state P-20 leaders provided seven common criteria for defining exemplary partnerships. P-20 partnership leaders provided insight about the resources necessary to promote partnership success from their perspective, describing 10 essential elements for exemplary P-20 partnerships. Participant interviews and surveys were examined in light of the Community Capitals Framework, revealing that social capital, human capital, and financial capital are perceived to be the most essential resources for developing exemplary P-20 partnerships. Based upon these findings, I recommend that educators and policymakers who desire to start or strengthen P-20 partnerships evaluate the social capital, human capital, and financial capital available in their communities and consider how those assets can be best utilized to support P-20 partnership success. Additionally, P-20 partnership leaders and participants would benefit from collaboratively assessing their work, evaluating partnership strengths against the essential elements for exemplary P-20 partnerships as expressed by the participants in this study.