This study investigates the relationship between characteristics of the living environment and antagonistic attitudes towards ethnic out-groups, with a focus on the explanation of opposition to ethnic intermarriage. Previous studies on the relationship between the living environment and prejudice-related attitudes used at most a limited set of contextual characteristics. We investigate to what extent relative group sizes, economic competition, cultural competition, safety threats, and social cohesion within Dutch municipalities and neighbourhoods affect antagonistic attitudes once social origin characteristics and other relevant individual-level characteristics are controlled for. To test hypotheses derived from Ethnic Competition Theory and Contact Theory, we used data from the Netherlands Kinship and Panel Survey supplemented with unique aggregate demographic statistics. The results show that proximity of ethnic out-group members in the municipality reduces opposition to ethnic heterogamy. However, an increase in the ethnic out-group proportion is positively related to opposition to ethnic intermarriage. Moreover, at the neighbourhood level, proximity of ethnic outgroups increases opposition among the lower educated, whereas it decreases opposition among the higher educated. These findings indicate that the threat mechanism, the contact mechanism, and selective migration operate at the same time. Economic competition is the only type of competition that evokes opposition to ethnic intermarriage.