Although almost all literature on burnout implicitly assumes that burnout is primarily caused by stressful employee-customer interactions, only a few studies have addressed this empirically. A principal-components analysis of a newly developed instrument assessing various forms of customer-related social stressors (CSS) in 3 different service jobs (N = 591) revealed 4 themes of CSS: disproportionate customer expectations, customer verbal aggression, disliked customers, and ambiguous customer expectations. These 4 CSS predict burnout beyond a variety of control variables. Contrary to other predictors of burnout analyzed in previous studies, the amount of variance explained in exhaustion (14%) by the 4 CSS scales is not higher than for personal accomplishment (14%) and is considerably lower than for depersonalization (23%).