Online TESOL courses can be categorized into asynchronous, synchronous, and a combination of these two modalities. Despite the two levels of separation that characterize asynchronous online TESOL courses, time and space, they can be as effective or even more effective than synchronous courses, which have to compensate only for one level of separation, space. Asynchronous online learning is more flexible and inclusive than synchronous online learning. Synchronous courses are more similar to on‐campus courses in terms of course materials and communication. Effective online TESOL programs are mainly asynchronous with a limited number of synchronous classes. This blended model of online instruction resembles flipped classrooms, in which learning is front‐loaded through asynchronous materials and communication and the synchronous class time is reserved for active learning activities. Effective online TESOL programs foster facilitating teaching presence, situated learning, social and cognitive presence, and deep learning.