This paper explores challenges in starting, developing, and incorporating partnerships between secondary and postsecondary education sectors. Site visits data from high schools, districts, and colleges across six Florida counties is used to identify the types of challenges educators faced in various phases of partnerships. We provide empirical evidence to support a conceptual framework based on a partnership model, which demonstrates that social capital and organizational capital are needed to create "partnership capital" to initiate and sustain partnerships. Whereas considerable collaborative resources are available to help higher-performing students prepare for selective universities, there is much less collaboration around improving college readiness. [This article was published in "Educational Policy" 2019.]