The current study aims to investigate the effects of a strategic plan developed by the involvement of the family, community, and Buddhist institutions in Thai vulnerable youth knowledge, attitudes, and behavioral changes. The sample included 302 vulnerable adolescents from Khon Kaen, Thailand. The utilization of systematic sampling was observed based on income, marital status, and neighborhood. 10 governmental employees also took part in an interview designed to investigate the participants' changes in behaviors of drug abuse. The instruments include a strategic plan for the drug prevention of vulnerable children, a test of drug prevention knowledge, a satisfaction survey, and a semi-structured interview. The data were obtained by a pre-post-test on the samples' knowledge of drug prevention, an attitude survey, and an authorities' interview. Frequency, percentage, mean score, SD, and t-test were used to examine the data. The content analysis assessed qualitative data. The findings reveal how a strategic plan designed by institutions concerned with human development led to the development of knowledge, attitudes, and positive behavioral changes among at-risk teenagers.