The aim of this research is to develop a Model for CSR Reporting based on the Global Reporting initiative, GRI Sustainability Reporting Guidelines G4, using an ontological approach. This Model can be used as a shared vocabulary and knowledge base. The Ontological Model is based on a combination of methodologies. This research adopts the methodology used to develop the CSR reporting ontology. This includes four phases: specification, conceptualization, formalization, and implementation. The specification phase defines the purpose and the scope. Conceptualization identifies the Conceptual Model. Formalization transforms the Conceptual Model using a Unified Modeling Language (UML) by following a top-down hierarchy approach. Implementation encodes the formalized Model using OWL. The resulting ontological Model for CSR Reporting users is based on GRI G4 and can be automatically processed.