Using Community-based and Tribal Participatory Research (CBPR/TPR) approaches, an academic-tribal partnership between the University of Washington Alcohol and Drug Abuse Institute and the Suquamish and Port Gamble S’Klallam Tribes developed a culturally grounded social skills intervention to promote increased cultural belonging and prevent substance abuse among tribal youth. Participation in the intervention, which used the Canoe Journey as a metaphor for life, was associated with increased hope, optimism, and self-efficacy and with reduced substance use, as well as with higher levels of cultural identity and knowledge about alcohol and drugs among high school-age tribal youth. These results provide preliminary support for the intervention curricula in promoting positive youth development, an optimistic future orientation, and the reduction of substance use among Native youth. (PsycINFO Database Record (c) 2017 APA, all rights reserved)