The number of firms supporting work from home has risen dramatically as advances in communication technology have fundamentally transformed the way humans cooperate. A growing literature addresses working from home, but focuses only on individual workers, overlooking potential influence of co-worker engagement. Our aim is to study the influence of co-workers working from home on individual and team performance. We use unique data from a large-scale survey involving nine European countries, 259 establishments, 869 teams and 11,011 employees to show that the impact of working from home by co-workers on performance is considerable and has remained hidden in past studies because they did not account for co-worker effects. While working from home may be useful for some workers, it does bring issues for them as well. Specifically, we demonstrate that co-workers working from home negatively impact employee performance. Moreover, team performance is worse when more co-workers are working from home.