Preservation of biodiversity and continued provision of ecosystem services increasingly relies on environmental conservation on private lands. Despite a multitude of past studies, our knowledge of the motives, opportunities, and challenges of private land conservation, especially on nonworking lands, where financial incentives are less relevant, remains incomplete. A key reason is that a variety of theoretical approaches, resulting in diverging study results, have been used to investigate private land conservation. To help remedy this problem, the current study rigorously examined several established social-psychological determinants of proenvironmental behaviors and developed a comprehensive model, which merged elements from previous studies, to investigate landowner participation in a government-sponsored private land conservation program for nonworking lands. The results are based on analysis of a mailed survey of 800 program-eligible landowners. Contrasting program participants with nonparticipants, we elicited information such as about values, worldviews, socio-demographic characteristics, and property attributes that led landowners to participate in this conservation program. The results of our study illustrate the complex relationships among values, worldviews, norms, attitudes, and behaviors emphasizing the importance of proenvironmental worldviews and of formal education for increasing the likelihood of enrollment in this government-sponsored private land conservation program. Against expectation, neither personal norms, household income, political leaning, nor the size of the eligible property area were found to be important in directly determining the decision to enroll in this conservation program. However, an association of political leaning with stated personal obligation for private land conservation was found. Our results highlight the relationship between formal education and achievement of private land conservation goals through governmental programs for nonworking lands; they also suggest opportunities for supporting conservation-minded landowners who are disinclined to engage in governmental programs. To our knowledge, the current study is the first to use a comprehensive model to systematically compare alternative concepts from social psychology such as values, worldviews, norms, and attitudes and their relationships with private land conservation.