This study combines insights from contact theory and social capital literature to study how ethnic diversity at work is associated to ethnic tolerance. It is argued that workplace ethnic diversity is related to ethnic tolerance in two ways: through interethnic contact and through interethnic social resources. The interrelation between these two mechanisms is also considered. The study relies on unique workplace survey data from the Netherlands (N = 3800) with information on ethnic tolerance, measured as support for immigrant entitlements. The results show that ethnic diversity in the workplace is positively related to interethnic contact and interethnic resources at work, and both of these are positively related to ethnic tolerance. However, the initial positive effect of interethnic contact on support for immigrant entitlements is mediated by interethnic resources, thereby showing that the interethnic resources mechanism is more insightful as to how ethnically diverse workplaces matter for ethnic tolerance.