This paper examines and provides examples of three distinct approaches to mobile learning in professional development (PD). First, mobile technologies are used to deliver and enhance PD for teachers. Examples of this type of mobile learning include online courses, mentoring via mobile devices, and participation in online professional communities. Second, mobile technologies can be used to support teachers by streamlining administrative tasks, enhancing classroom instruction, and facilitating communication with parents, colleagues and students. Finally, PD may be focused on teaching educators how to integrate mobile technologies into their classroom instruction.