Investigations of the causal relationship between organizational commitment and job satisfaction have yielded contradictory findings. Little empirical research has looked at this complex relationship in the context of work effort. The purpose of this study was to determine how these variables interact in the service environment. Using a sample of 425 employees in two service organizations, the author tested two structural equation models. The hypothesized model with organizational commitment as a moderator between job satisfaction and service effort fit better than a model with job satisfaction as moderator did. Conceptual implications are discussed, and suggestions for future research are made.