The numerous advantages of using open learning resources (OER), raised the awareness to teachers' difficulties in using and developing these materials. This study explores the enablers and inhibitors teachers face in the adoption of OER, teachers' attitudes towards OER and their educational approaches. Analyzing the participants' answers to the questionnaires and interviews, demonstrated a distinction between the enablers and inhibitors in the usage of OER. The findings show that the more teachers perceive OER as enhancing the learners' attainments and improving the latter's satisfaction, the wider the usage of OER. Regarding the enablers, the findings illustrate that teachers believe the OER should be easy to trace, include curriculum-based materials and be easily changed and edited. Moreover, they have to be up-to-date and on a high level of thinking, easy to use and provide detailed explanations about their usage. When planning the OER, teachers' pedagogical autonomy must be reinforced in order to promote their chances of a successful implementation. As for the factors that inhibit the usage of OER, the teachers mention three main factors: accessibility, pedagogical quality and technical difficulties.