The model of effort-reward imbalance, with its 2 components effort-reward imbalance (ERI) and overcommitment (OC), has proven its significance in the area of work stress and occupational health. The 2 aims of the present study were to study the relationships of the 2 model components ERI (as a measure of chronic work stress) and OC (as a person variable) with self-rated emotional exhaustion (as a personal outcome) as well as supervisor-rated job performance (as an organizational outcome). Second, we tested the often neglected interaction hypothesis of the model, which proposes that OC potentiates the detrimental relationships between ERI and respective outcome variables. We applied multilevel modeling based on data from 152 employees nested in 20 teams from a German manufacturing company. Our results showed that ERI was positively related to emotional exhaustion and negatively related to supervisor-rated job performance, whereas OC was unrelated to emotional exhaustion and job performance. Testing the interaction hypothesis by taking OC into account as a moderator, our data showed that OC significantly aggravated the associations between ERI and emotional exhaustion, as well as ERI and job performance. We discuss limitations and implications for future research and practice.