Our study details the development of the Positive Youth Development Sustainability Scale, a self-reporting tool to assess the impacts of positive youth development (PYD) programs. The Positive Youth Development Sustainability Scale provides practitioners a tool in the field of PYD both domestically and internationally, addressing the concern of global application and sustainability criteria (e.g., resilience and happiness). First, we conducted a detailed literature review on existing PYD program assessment techniques. Next, we conducted an exploratory factor analysis, via SPSS and AMOS software, to establish the number of factors in the scale. The constructs of the five-Cs model (Lerner, 2005; competence, confidence, character, connection, and caring) along with the sixth C (contribution) and happiness were confirmed into six factors. Confirmatory factor analysis was conducted using 2 samples from rural areas of Thailand and the Phoenix, Arizona, metro area (n = 580 and n = 407, respectively). Our analysis shows the factor structure was highly comparable with mean comparative fit indices of .930 (Thailand) and .933 (Phoenix metro) for Grades 9–12 and 3–6, respectively. Our study suggests that the tool can be used in different settings and demographics for PYD programs. Future studies should look at the impacts of PYD programs over long periods of time and in a wide range of grades, cultures, and countries to reaffirm multiple applications in various settings.