The present research uniquely sheds light on the practices of Humanistic Buddhism (a form of Engaged Buddhism most prevalent in modern Taiwan), which have been completely neglected in contemplative science. It also explores the social and ecological implications of contemplative practice, another under-investigated area of research. By investigating the effects of a Buddhist monastic retreat on pro-social and pro-environmental behavior, this study stands to contribute significantly toward filling the gap in current contemplative research. A total of 30 participants in the Fo Guang Buddhist monastic retreat were surveyed before and after receiving one month of training in both “social mindfulness” (tending to the needs of others in situations of interdependence) and silent meditation. Observations were recorded of pro-environmental behaviors, including decreases in food waste, and pro-social behaviors, such as donations made to a charitable organization with the money used to compensate retreatants for their participation. Oxytocin, a hormone associated with compassion, was measured via saliva. Participants also reported on their inner experiences during a set of distinct forms of contemplative practice. Main findings include a notable increase in pro-environmental behaviors with minimal changes in pro-sociality. Participants reported feeling greater connection to nature and the community by the end of the retreat. The overall trend involved a shift away from egocentric concerns toward a more ecocentric worldview. In summary, this study serves as a foundation for future research in the area of ecology and mindfulness. It provides evidence that mindfulness, as cultivated in a context emphasizing Humanistic Buddhist values such as caring for other beings and the natural world, has positive implications for the environment and ecological well-being. By investigating Buddhist practices in a traditional monastic setting and taking culture into consideration, it gives credit to context, a missing piece in much of the previous research in contemplative science.