As companies engage in business model (BM) innovation, they increasingly turn to BM tools, such as the Business Model Canvas, the STOF framework, or e3-value ontology. The main advantages associated with these tools are that they establish a standard lexicon, or common language, within an organization. Despite the increasing scholarly interest in BM tools, we still lack theoretical foundations and empirical evidence for understanding their roles and uses in BM innovation. In this article, we argue for conceptualizing BM tools (i.e. models, methods, and IT support), as boundary objects that must have the capacities to overcome the knowledge boundaries between different communities of practice. Based on empirical insights from six case studies and an in-depth field study, we make three contributions: First, we identify five typical communities of practice involved in BM innovation in large organizations. Second, we analyze the knowledge boundaries between them. Third, we discuss implications for BM tool design as boundary objects with syntactic, semantic, and pragmatic capacities.