A growing portion of teaching materials are available online. How is this development affecting the role of libraries at research universities and universities of applied sciences? Although some libraries in the Netherlands are already seeking to tailor their services to reflect this new trend, most are still working to develop an appropriate response. So far, their support activities have been oriented towards ‘online’ rather than ‘open’ teaching materials. In the United States, libraries play a prominent role in the area of OER support. However, this support appears to be limited to the domains traditionally associated with libraries: content and collections. Library support for blended learning and the creation of interactive learning materials is somewhat less advanced. Which differences and similarities can we identify between the Dutch and American situations, and which US examples would be worth emulating here in the Netherlands? Does the Netherlands need an OER librarian?