In this paper, we present an ontology of educational theories their relation to learning design. This ontology takes into account learning design (LD) specifications such as OUNL-EML and IMS-LD at the conceptual level (1), semantic web standards such as OWL at the formal level (2), as well as JAVA standards at the implementation level (3). This ontology is intended to provide a knowledge base for any IMS-LD compliant authoring systems/LKMS, in order to provide services to authors of LD scenarios. The ontological engineering (OE) has been done using the Hozo ontology editor at levels 1 and 2 respectively.