The purpose of this study was to determine the causes of un-Islamic behaviors among at-risk Muslim youth in the three Southern border provinces of Thailand. The key informants of the study consisted of 30 Muslim youth who demonstrated at-risk behaviors, 15 Muslim leaders, and 15 Muslim academicians. Data were collected through in-depth interviews, and a content analysis was performed using logical comparison with related concepts, theories, and research reports. The results of the study revealed that the at-risk, un-Islamic behaviors of the youth in the three Southern border provinces could be attributed to (1) the absence of breastfeeding as an infant; (2) a lack of a close Islamic upbringing (3) little interest in Islamic activities; (4) Muslim leaders’ negligence in looking after youth and (5) apathetic and insufficient study of Islam.