This document provides an overview of Open Educational Resources (OER), Open Textbooks, and Massive Open Online Courses (MOOCs). It discusses the emergence and definitions of these concepts. OER emerged from "learning objects" and were further developed through open licensing models. They are educational resources that can be freely used and reused. Open Textbooks similarly aim to increase access through open licensing. MOOCs emerged later and aim to provide open online courses to large numbers of students. The document examines factors influencing how easily educators and students in the global south can use and adapt these resources.