How does an increased presence of immigrants in the workplace affect anti-immigration voting behavior? While cooperative interactions between natives and immigrants can reduce intergroup prejudice, immigrant coworkers might be regarded as a threat to native-born workers’ labor market position. We combine detailed Swedish workplace data with precinct-level election outcomes for a large anti-immigration party (the Sweden Democrats) to study how the share of non-Europeans in the workplace affects opposition to immigration. We show that the share of non-Europeans in the workplace has a negative effect on support for the Sweden Democrats and that this effect is solely driven by same-skill contact in small workplaces. We interpret these results as supporting the so-called contact hypothesis: that increased interactions with minorities can reduce opposition to immigration among native-born voters, which, in turn, leads to lower support for anti-immigration parties.