In Communication Science, international scholarly communication and collaboration practice still remain unknown territory. Therefore, a systematic review of the state of the art on scholarly communication practice in international research collaborations (IRCs) was carried out that included a broad spectrum of disciplines and research fields such as Communication Science, Business and Management Studies, Sociology, science studies, and the science of team science. A sample of 168 contributions focusing on IRCs were identified. The paper outlines focus and methodological designs of those contributions, provides insights into the composition of the observed IRCs, summarizes the perspectives of the disciplines and research fields, presents the insights into communication structures and processes in IRCs, and discusses the aspect of team diversity, which some studies indicate as relevant for communication practice in IRCs. Overall, research largely focuses on the structural dimension of communication, while empirical analyses on the actual communication processes among scientists in IRCs are still rare. Secondly, research is missing on how team complexity is dealt with in IRCs and what impact it has on collaboration processes and success. A third and fourth research gap are identified regarding the use of a joint collaboration language and the communication processes in Social Sciences and Humanities. Future research should broaden its analytical focus to fill those gaps. This would provide important insights from an epistemological and a practical perspective, by offering the foundation for the development of guidelines and toolkits for future IRCs, thus contributing to the success of such forms of research and knowledge creation.