As open educational resources (OER) expand in the US and elsewhere, attention should be paid to the challenges of implementing OER and solutions to those challenges. OER currently hold great promise for instructing students in K-12 (secondary) and primary school classrooms, because -unlike traditional curriculum materials -OER content can legally and freely be copied, used, adapted and reshared by anyone. Notwithstanding the benefits, OER developers have not yet worked out certain structural issues that can make it difficult for teachers and students to use OER, impeding the adoption and broader acceptance of even the best designed OER curricula. Links which disappear over time, device management, data and privacy concerns, quality, scope, sequence and alignment challenges, copyright issues and sustainability of OER curricula are all challenges that advocates of OER and curriculum designers often miss, ignore or avoid. These challenges, however, can be overcome through thoughtful planning and partnerships, as has been done in the US with the successful Louisiana Guidebooks and other OER course materials.