Open Educational Resources, commonly abbreviated as OER, are teaching, learning and research materials that are in the public domain or released under an open licence that permits specified forms of reuse. Examples include textbooks, lecture notes, lesson plans, worksheets, videos, images, simulations, datasets, assessments and complete courses. The defining feature of OER is not simply that the material can be viewed without payment.
Open licensing provides users with legal permissions that may include copying, adapting, translating, combining and redistributing the material, subject to the terms of the particular licence. This distinction separates OER from ordinary free online content, which may be accessible without charge while remaining fully protected by copyright with no general permission for reuse.
The concept of open educational resources developed alongside movements for open access, digital publishing and expanded educational access. The internet made it technically inexpensive to distribute educational materials widely, while open licensing frameworks provided mechanisms for granting advance permission for reuse. Creative Commons licences became particularly important because they allow copyright holders to specify permissions and restrictions in standardised forms.
Some licences permit broad adaptation and redistribution, while others impose conditions such as attribution, non commercial use or distribution under the same licence. The legal details therefore matter. A resource should not be described as fully open merely because its author states that it is free unless the relevant reuse permissions are clear.
OER can reduce barriers to educational materials because learners and educators can access resources without purchasing conventional editions in many cases. Teachers can adapt openly licensed materials to match local curricula, learner abilities, language requirements and cultural contexts. A lecturer can combine several openly licensed chapters into a course pack, translate a resource into another language where permitted, or update information that has become outdated. This adaptability is one of the central educational advantages of OER. Traditional resources can be difficult to modify because copyright restrictions may prohibit alteration even when a teacher owns a lawful copy. Open licences can therefore change not only the cost of access but also the possibilities for educational adaptation.
The five R framework is commonly used to explain major forms of permission associated with open educational practice. These are retain, reuse, revise, remix and redistribute. Retain means keeping a copy, reuse means using the material in different contexts, revise means adapting or modifying it, remix means combining it with other material to create something new, and redistribute means sharing copies or adaptations with others. The precise legal permissions depend on the licence. For example, some Creative Commons licences permit adaptation while others restrict it, and some prohibit commercial use. Users must therefore read the licence rather than assuming that all OER permit identical activities.
OER can be used across educational sectors and subjects. Open textbooks can provide alternatives to expensive commercial textbooks. Open lesson plans can help teachers develop classroom activities. Open datasets can support research and data analysis. Open videos can provide demonstrations, explanations and recorded lectures. Open simulations can allow learners to experiment with scientific or technical concepts. Institutions can also develop open courses by combining multiple openly licensed resources into coherent learning pathways. The usefulness of OER depends on quality, currency, accessibility, licensing clarity, educational relevance and the ability of educators to adapt materials appropriately. Openness removes some legal barriers but does not automatically establish pedagogical quality.
OER also raises questions about attribution, quality assurance and sustainability. Authors need to receive appropriate credit where the licence requires attribution, and users need to preserve relevant licensing information when redistributing adapted materials. Quality assurance can be decentralised because openly licensed resources may be produced by universities, teachers, governments, charities, individuals and collaborative communities. This diversity can be beneficial but means that users should evaluate accuracy and suitability rather than assuming that open resources are authoritative. Sustainability can also be challenging because maintaining, updating and reviewing resources requires time and expertise even when distribution itself is inexpensive.
OER should be distinguished carefully from free resources, open access publications, public domain works and open source software. Free resources may be available without payment but may not permit copying or adaptation. Open access usually concerns access to scholarly research literature and does not necessarily imply the same reuse permissions as OER. Public domain material has no applicable copyright restrictions in the relevant jurisdiction, although other rights can sometimes remain relevant. Open source software concerns software licensing rather than educational content, although educational projects can combine open source software with OER. These distinctions are essential because the legal and practical freedoms associated with each category differ.
OER can contribute to affordability, educational collaboration, localisation, curriculum adaptation and knowledge sharing. Its impact depends on institutions and educators having the time, skills and infrastructure needed to discover, evaluate, adapt and maintain resources. Open licensing also does not remove all restrictions because privacy, trademarks, image rights and other legal considerations can remain relevant. OER is therefore best understood as an approach to educational resource creation and sharing based on meaningful reuse permissions. Its central contribution is the ability to treat educational materials as resources that can legally be adapted and redistributed under their stated licence rather than merely as content that happens to be available online.
