This article explores similarities between English as a lingua franca (ELF) and International Sign (IS), two lingua franca phenomena which in the last decades have been subject to increasing, albeit independent, linguistic research. In contrast to spoken intercultural communication, in which English often represents a shared resource that speakers from different linguacultural backgrounds draw on, in the visual-gestural modality no specific sign language has yet gained such global reach. Instead, in many international contexts IS is used: a lingua franca that can be more or less conventionalized and that is not based on one particular sign language. IS use depends on the communicative situation, in which signers flexibly and creatively use different signs from natural sign languages as well as iconic elements and gestures. Despite overt formal differences between ELF and IS, when focusing on the actual communication process, rather than the forms that result from it, the two lingua franca phenomena share many similarities. In fact, both ELF and IS are variable communicative means that get situationally adapted by speakers and signers on the basis of different resources they have at their disposal. Similar discussions about the difficulty of conceptualizing ELF and IS, about the role of multilingual resources, and about interaction processes at play can thus be found in both ELF and IS literature. This insight opens up new possibilities for researchers in the two fields to mutually benefit from the study of lingua franca communication in the other modality, which prompts the need for a cross-modal collaboration between ELF and IS researchers.