OER Knowledge CloudJournal ArticleSiren, AnniBekirsky, LiamEducational Resource repositories are a common tool used by institutions and organizations – public and private – to provide spaces to gather and access resources. We conducted a historical review of 152 OER repositories from the past two decades, identified through a comprehensive review of academic literature. This revealed that a large proportion of formerly acclaimed OER platforms are now inactive or defunct – some even by the time of publication of the papers that cite them – raising questions about their impact and sustainability. We investigated sociotechnical and institutional factors potentially affecting the lifespan of these platforms, including funding type, the presence or lack of community-building tools and user contributions, and types of ownership, platform, resource, and access. This study also outlines inconsistencies in the terminology and criteria used to define OER repositories and proposes a clarifying typology to differentiate them from other resource platforms, such as referatories and proprietary Open Access resource platforms. This research does not provide definitive reasons for the failure of repositories but establishes a foundation for future research on the longevity, sustainability, and evolution of OER infrastructures.20262026/01/29EnglishDistance Education1-22CanadaCanada10.1080/01587919.2026.2618801https://www.tandfonline.com/doi/full/10.1080/01587919.2026.26188010158-7919yesopen educational infrastructureopen education resourcesOERlearning object repositoryplatform sustainabilityhttps://www.tandfonline.com/doi/full/10.1080/01587919.2026.2618801siren-bekirsky-2026.pdfCanada, United Kingdom, North America