Teacher education nowadays needs a change in vision and action to cater to the demands of changing societies. Reforms, improvements, and new approaches in teacher education are an immediate need. Online training of teachers using OER has emerged as a new approach in this direction. This approach is based on the assumption that online training will facilitate mass training of teachers as per their convenience and ease and will be helpful in filling the huge gap in demand for skilled teachers. The other assumption is that being OER-based training, it will be easy to adapt it to different cultures and languages. Considering these assumptions, the present paper discusses about on-going initiatives of online training of teachers in different parts of the world; focuses on promises of using OER to make online training of teachers more relevant and up-to-date; and suggests potential strategies for effectively using OER for initial training and continuing professional learning of teachers in online settings.