As ecological crises increase and intensify while the world economy continues to expand, humanity faces a goal conflict between economic growth and planetary sustainability. The project GROVAINITY integrates the focus of Environmental Psychology on individual behaviour and insights from International Relations into broader institutional dynamics to study how this goal conflict plays out in international organisations (IOs), whose work shapes sustainability transitions. Using a mixed-methods research design, we explore how IO officials conceptualise the relationship between growth and sustainability. Our research project will produce novel findings and targeted outputs for society at large (report), as well as practitioners (workshop) and scientists (publication) interested in how this goal conflict undermines efforts to stay within planetary boundaries.