Decision-making in environmental systems (such as lakes and watersheds) is often highly contested, involving multiple stakeholders with competing interests and conflicting certitudes. Quantitative models are an essential tool for informing decision-making in these contexts. Models which produce unpopular predictions, however, are frequently challenged, and if not adequately defended may be rendered obsolete. Blind faith in models is equally damaging, as failure to acknowledge limitations can lead to inappropriate usage, undermining long-term trust in useful models. This talk proposes that models are most useful when stakeholders build informed trust: a realistic perspective on what the model can and can’t, do, and why. Here I propose that the process of building enough, but not too much, trust in models relies on building meaningful relationships between modellers and stakeholders over the life cycle of modelling projects. Since building informed trust takes time, money and skill, it needs to appropriately resourced, as an essential component of project design and budget. I also discuss some of the key skills in engaging across boundaries in order to build inform trust, and how these skills are built in the workforce.