This paper uses data from the National Hockey League (NHL) to consider the potential gains to firms from employing culturally diverse work teams. It finds that the presence of foreign workers does increase firm-level performance: NHL teams that employed a higher proportion of European players performed better. However, the results also indicate that teams perform better when their European players come from the same country rather than being spread across many European countries. When teams have players from a wide array of European countries, integration costs associated with language and cultural differences may start to override any gains from diversity.