<p>The conceptualization and development of teachers’ professional digital competence (PDC) has increasingly captured the interest of international researchers in the last decades. This interest coincides with the global trend of incorporating digital tools and resources into educational environments, with policy frameworks and implementation not always being in step with research. This review of systematic reviews aims to further our understanding of relational aspects in the development of teachers’ professional digital competence: the relations between teachers’ individual professional digital competence development and other influencing factors and contexts. A framework synthesis approach is utilized to analyse and synthesis 20 selected review studies. The findings are visualized in terms of three interrelated ecosystems, between teachers and (1) colleagues, leaders and professional development, (2) students, pedagogical practices and teacher beliefs, and (3) policy, physical environment and resources and technology. A model for including relational aspects in PDC development is presented, and research-based recommendations are provided for researchers, practitioners and policy makers focusing on development of in-service teachers’ PDC.</p>