The paper presents an ontology-based framework for capturing and explicit representation of the actual context of use of a specific learning object (LO) in a specific learning design (LD). Learning context related data represented in such a manner provides a solid ground for personalization of both LOs and LDs. The core part of the proposed framework is a LO Context ontology, that leverages a range of other kinds of learning ontologies (e.g. user modeling ontology, domain ontology, LD ontology etc.) to capture the information about the real usage of a LO inside a LD. Additionally, we present the architecture of an adaptive educational system based on the suggested framework, in order to illustrate the benefits of our proposal for personalization of LD.