The Young Women's Preparatory Network (YWPN) is a private foundation that supports single-sex, college preparatory schools throughout Texas. Over the past fifteen years, the organization has worked through public-private partnerships to establish and support public, all-girls secondary schools in districts across Texas. This study evaluated the effects of attending the seven established all-girls schools in the YWPN, relative to attending a co-educational school in the same district, on attendees' educational trajectories. This evaluation took a high level view of understanding the effects of attending YWPN schools, focusing on average effects for students who attended one of seven schools in the YWPN network between 2007-08 and 2014-15. These schools were established and are supported through a partnership between the public independent school districts and the YWPN foundation. The primary policy implication of this study is that sustained support for these partnerships is warranted in light of the schools' beneficial impacts on academic performance and behavior during middle school and their marked positive impacts on college enrollment.