This study aims to involve the institutions of family, community, and Buddhism in designing a training course that could enhance vulnerable youths' knowledge of unintentional pregnancy prevention. The attitude toward the involvement of the three stakeholders and changes in teens' behaviors are also the center of the investigation. 302 vulnerable teenagers from Khon Kaen, Thailand, were sampled. Purposeful sampling was used. Income, marital status, and neighborhood were used to choose participants. 10 public workers responsible for protecting vulnerable youth were also sampled to take part in an interview session aiming to investigate participants' behaviors. The instruments consist of a training course for vulnerable youth unintended pregnancy prevention, a test for unintended pregnancy prevention knowledge, a satisfaction questionnaire, and a semi-structured interview. Frequency, percentage, mean score, SD, and t-test were used to examine the data. The content analysis assessed qualitative data. The results study illustrates how a training course developed with the collaboration between institutions concerned with human development led to the development of knowledge, attitudes, and positive behavioral changes among vulnerable youths.