Puerto Rico Optimal System ChAnge (PROSa) - Puerto Rico has a high need for teen pregnancy prevention interventions. Evidence of this is that the rate of teen pregnancy is more than 50% higher than that of the U.S. (28.9 vs. 18.8 per 1,000 teens). Considering these highly rates, the Nexos Group, Inc. – an applied research and technical assistance community organization specializing in the evaluation of health programs, human services and public health issues, public health research, translation and cultural adaptation of evidence-based practices, and the development of methodologies to measure program effectiveness and performance - with existing community partners Coalición de Prevención Moroveña, Inc., Sor Isolina Ferre Centers, Inc., and Urban Strategies, LCD propose to enhance current efforts and collaborations to promote positive youth development, sexual and reproductive health outcomes, and advance health equity for adolescents, their families, and communities. In specific, to engine and promote a platform to improve the optimal health of adolescents and reduce teen pregnancy and sexually transmitted infections (STIs). The Puerto Rico Optimal System Change (PROSa) will scale-up experiences following a collective impact, community engagement and system thinking approach to significantly improve the optimal health of youth and their families and to reduce teen pregnancy through the saturation of services to implement a set of three evidence based practices (Friends, SMART Plus, Love Notes EBPs), as well as provide comprehensive supportive and youth friendly spaces/services throughout rural central and north-east urban counties in Puerto Rico (Morovis, Orocovis, Ciales, Jayuya, Vega Alta, Loíza and Canóvanas) whose teen birth rates are higher than the local and national averages and are disproportionally affected by STIs. Thru PROSa, we aim to channel equity opportunities, improve the optimal health of adolescents, and reduce teen pregnancy and STIs and associated risk behaviors through the engagement of communities with the greatest needs and disparities. PROSa’s purpose is to reduce teenage pregnancy and behavioral risk factors underlying teenage pregnancy; and develop knowledge on best practices for broader populations and cultures. PROSa aims to: 1) replicate effective programs and comprehensive supportive and youth friendly services and spaces with youths, trusted adults (e.g., caregivers, school staff) and community key stakeholders to promote the optimal health of youths; 2) ensure PROSas’ activities and efforts are of the highest quality and best fit for youth, families and community members by following System Thinking and Community Engagement approaches for the improvement of youth health outcomes; 3) stimulate capacity and dissemination of teen pregnancy updated information, success stories, lessons learned, and youth voices to relevant stakeholders and community at large for long-term sustainability; 4) provoke a system shift at municipal level through capacity building and community engagement to address youth optimal health. PROSa’s project components includes: 1) Implementation of three EBPs to prevent teen pregnancy and promote the optimal health of youths; 2) Increased access to high-quality sexual/reproductive health and friendly services and spaces; 3) Community immersion and activation strategies (e.g., Gnzrs-Advzrs, Youth Town Hall Meetings, Photovoice, Family Champions, and Social Media); 4) Engagement of key multisectoral stakeholders on teen pregnancy prevention; and 5) Integrated Community Equity Component (e.g., Family Champion and Youth Financial Coaching Initiatives) that will have a key role in the process of ensuring that the project incorporates meaningful and authentic engagement of youth, families, and caregivers throughout the development, implementation, and evaluation. PROSa will directly reach at least 5,525 youth and 940 caregivers, school staff and other community key stakeholders (15.4% of adults) over the course of Y1 to Y5.