Although prior literature reveals that loneliness is a pervasive problem among adults, little research has evaluated the impact of loneliness in the workplace. Given that workplace relationships underlie many important organizational phenomena, it is important to understand whether and how workplace loneliness affects employee behavior. Based on the social exchange model, we hypothesize that in comparison with their non-lonely counterparts, lonely employees will experience lower quality leader-member and organization-member exchanges at work such that they will tend to be worse at in-role and extra-role workplace functions. Drawing on the results of our survey of schoolteachers, we present findings to support our hypotheses. © 2012 Copyright Taylor and Francis Group, LLC.