Over the past decades, the theatrical landscape of Brussels has increasingly reflected its multicultural everyday reality on stage. Today's multilingual productions pose a heightened challenge to the contemporary theatre translator, resulting in various experiments with modes of on-stage translation. Notwithstanding, the translator's role in the production process has been largely overlooked in academic research. The current study seeks to fill this gap by exposing the underlying agency networks of theatre translation, focussing on practitioner and process rather than translation product. Responding to a bias of research frameworks prevailing in translation studies, it departs from methodologies developed in theatre studies, as to integrate both academic disciplines and induce a much needed 'processual turn' in theatre translation studies. Translation modes in focus are mimetic interlingual surtitling, playful surtitling, simultaneous translation and automatic machine translation. First analysing in what way dramaturgical considerations of multilingual performance texts motivate the selected translation modes, the study continues to expose how the translator’s agency is conceptualized in relation to other theatre practitioners. Through a multiple case study of postdramatic performances by Brussels-based companies, the project aims to provide practitioners with a framework for negotiating multilingualism on stage and strengthen the nexus between university and arts sector.