Open educational resources (OERs) have become a key element in the development of quality education within the 2030 Agenda. This article discusses the current situation of OER in Spanish universities, analysing their publishing platforms, policies, strategies and incentives for authors. In addition, the characteristics of the existing OERs in institutional repositories are analysed and a proposal for development stages, according to their purpose and level of openness, is presented. This study concludes that, although there is growing interest in OER, there is currently no general awareness of what OER is or what its creation entails. Interdisciplinary cooperation of the professionals involved is, therefore, essential to create OER that can be found, shared and reused.