<p>Mongolian pastoralists have social norms for using different pastures in different seasons, which contributes to the sustainable utilization of grasslands. However, as the economy develops, individuals’ morals may change, such that the social norms for the use of grassland resources may not be maintained. This study explores how economic development in Mongolia relates to pastoralists’ moral judgments and how it relates to the social norms regarding the use of communal grasslands. We collected data from 480 households in four areas close to an urban area where the market economy is more developed and in four remote areas of Mongolia. Using these data, we estimated econometric models showing the factors affecting moral judgments and their effects on social norms. The results show that better access to urban areas is associated with more consequentialist and libertarian herders and less deontology and communitarian herders and consequentialist and libertarian morals are negatively associated with social norms for grassland use. These results suggest that as market economies penetrate rural areas, people’s morality changes, and social norms based on traditional communal cohesion and mutual aid will be less likely to be maintained. These findings suggest that policymakers should apply intervention methods acceptable to libertarians and consequentialists, who are increasing with economic development.</p>