Research shows that professional learning communities of teachers support their professional development. The Department of Science Teaching at the Weizmann Institute of Science in Israel operates ten learning communities of high-school physics teachers, spread throughout the country, who meet face to face once in two weeks over the school year. Since the framework of these face to face communities was found to promote teachers' professional development, it was adopted to an online community, thus enabling more teachers to participate. The model of the online community was developed, enacted and studied in three one-year iterations. The first iteration employed a participatory design methodology with teachers, leading teachers from the face-to-face communities and experts from the physics group of the Science Teaching Department. The model program is hybrid, integrating several face to face meetings during the year and video conference meetings of 90 minutes taking place once in a week throughout the school year. The total number of the program is 60 academic hours. We describe the goals, activities and ways of enacting the face to face communities, as well as the model developed for the online community. Research goals are to explore the challenges of the online environment, the professional development of the teachers as a result of participating in the online community, the existence of central characteristics of a learning community, and teachers' views regarding the contribution of the learning community. We collected and analyzed video recordings of the community meetings, interviews and feedback questionnaires. Challenges emerged mainly due to the limitations in visibility in video meetings. This led to changes in the design of the online environment and the activities. Findings indicate that the model supports teachers' professional development and the creation of a professional learning community. Teachers' participation in the online community enabled them to be active and productive over the course of the meetings. Being a part of the community provided teachers with the feeling that they are not working alone, and that they have the opportunity to consult, discuss and share with peers and experts. Teachers implemented in their classrooms activities they experienced in the meetings and brought to the meetings evidence about their practice and their students' learning for collaborative reflection with their peers. Teachers became aware of their ability to make genuine changes in their students' ways of learning. This research contributes to the current body of knowledge regarding teachers' professional development through the framework of an online community.