The goal of this synthesis is to review literature on the use of telecollaborative pedagogy for the purpose of language teacher education in order to identify themes in teacher intercultural telecollaborative learning. The synthesis reviews 36 telecollaborative studies that were published between 2009 and 2019 and focused on teacher professional development. Thematic analyses of the 36 studies revealed six themes: (a) changes in the focus from exploring telecollaborative learning to examining its application for teacher learning of new competences related to intercultural learning, technology integration, and telecollaboration integration; (b) conceptualization and design of telecollaboration as experiential learning for teacher professional development; (c) intentional enhancement of the transferability of new competences to future teaching; (d) teaching presence and expanded roles of project instructors; (e) explorations of teachers' changing attitudes and perceptions of telecollaborative learning; and (f) teacher preparedness for addressing challenges occurring in telecollaboration. Finally, this systematic review discusses the interrelationship among the six themes and offers implications for future research and practice in line with the current findings.