Sources of free online teaching courses include the University of Massachusetts at Boston, PBS and The Open University. These classes are not eligible for college credit, but they can suffice as professional development or continuing education credits.
The University of Massachusetts offers a class on early education care by Professor Mary Lu Love. The class seeks to help early childhood educators assess their skills with infants, toddlers and preschool children.
TeacherLine is a service for teacher professional development that is operated by PBS. The service offers some free courses, such as Positive Behavior in Schools I: Introduction to School-wide Behavior Systems.
The Open University offers teaching courses in multiple languages, including English and Chinese. Free courses in mentoring students, classroom research and learning to teach are available, as of 2015.