In line with previous research calls for greater alignment of the public with the private sector practices, this study highlights the significance of investigating organizational service orientation in public organizations, incorporating also internal customer and internal supplier satisfaction. The study incorporates a detailed statistical analysis (Instrumental Variables approach) to examine the relationship between Organizational Service Orientation and Job Satisfaction. This study utilized responses from 511 front-line employees in the public sector. Given the fact that Instrumental Variables approach controls for endogeneity, we can safely infer the existence of an interactive relationship between Organizational Service Orientation and Job Satisfaction. As with any study, several limitations may apply, including other factors that could intervene in the relationship between OSO and JS, greater sample size, and investigation among individuals of a single nationality. The findings of this study highlight the need to take initiatives towards enhancing public front-line employees‟ satisfaction as internal customers, and in turn their job satisfaction for improving delivery of services in public organizations. Our findings extend the line of research in service related theory within the public sector. Interestingly, the interactive relationship between Organizational Service Orientation and Job Satisfaction is also new to the private domain.