In light of globalization and advancements in communication technologies, telecollaboration is increasingly used for promoting the professional development of language teachers. However, very few reviews have been conducted to examine teachers' telecollaborative learning. To address this gap, this study provides a systematic review of 56 telecollaborative studies that focused on teacher professional learning and were published between 2010 and 2020. The study aims to address the following two questions: What are the main characteristics of methodologies used in teacher telecollaborative studies? What are the main characteristics of pedagogical applications of teacher telecollaborative studies? Besides reporting on emerging methodological trends among the primary studies, this synthesis uncovers three patterns in the pedagogical applications: (a) diversification of mixed pedagogical models, (b) increased integration of pedagogical mentoring across telecollaborative learning stages, and (c) increased integration of telecollaboration in classroom practices. These findings offer implications for future research and practice in the field of language teacher education.