The meaning of Publicness for organizations and for individuals has received growing attention in the public administration literature in recent years. We adopt a perceived publicness perspective to expand our understanding of the publicness concept and operationalize this perception as a means to predict employees' formal and prosocial behaviors across sectors. Using a recently developed Publicness Perceptions Scale (PPS), we present and empirically examine a model regarding the direct and indirect relationships among perceived publicness, employees' engagement, and their performance in public and hybrid organizations. Findings based on a field study of 340 employees from governmental (i.e. public) and non-governmental (i.e. hybrid) organizations reveal that perceived publicness has a positive relationship with Organizational Citizenship Behaviors (OCB) and that this relationship is largely mediated by employees' engagement. In addition, in non-government organizations perceived publicness is negatively related to employees' in-role performance. We thus contribute to the theoretical knowledge on publicness at the perceptual level and point to its role in formal and informal performance across sectors. Other theoretical, methodological, and practical implications are discussed, and directions for future studies are suggested.