Open Access (OA) and OER are related, but different!
At this moment, there is overlap between the two, but this may change!
OpenCourseWare (OCW), initially developed by MIT in 2001 is an initiative to share their course content for free and online to everyone, not just MIT students. This movement has grown and is now offered from a number of other learning institutions. Listed here are several, but not all, institutions that offer OCW.
The Courses in this section are not necessarily "true" OER, and some of them might contain contain features with a paywall-- but they all have at least some free content that may be useful with your teaching. If you are seeking "true" OER courses that you can modify, redistribute, and own the licenses to, check out Cool4Ed and OER Commons on the "Where to Find OER" tab of this guide.