Founded by Harvard University and MIT in 2012, edX is an online learning destination and MOOC provider, offering high-quality courses from the world’s best universities and institutions to learners everywhere.

MIT OpenCourseWare is a cornerstone of MIT’s ongoing commitment to openly sharing educational resources. It is one of the oldest online education sources, founded in 2001.

MOOC List is a website where you can find free online courses (MOOCs) offered by the best universities around the world.

Stanford Engineering Everywhere (SEE) expands the Stanford experience to students and educators online and at no charge. A computer and an Internet connection are all you need. The SEE course portfolio includes one of Stanford's most popular sequences: the three-course Introduction to Computer Science, taken by the majority of Stanford’s undergraduates, as well as more advanced courses in artificial intelligence and electrical engineering.

Udemy is a site that allows anyone to build or take online courses.Each of their 35,000+ courses is taught by an expert instructor, and every course is available on-demand, so students can learn at their own pace, on their own time, and on any device.