Green façades, on which plants grow, are increasingly prominent in research and industry. They provide benefits beyond conventional façades. All façades act as a buffer between the outdoor and indoor environment, regulating heat, moisture, light, pollutants and sound. Green façades carry these forward—reducing the urban heat island effect, boosting biodiversity, providing food, improving the microclimate for sound and air quality, and increasing access to nature, which has major benefits for health. Research to date has primarily examined isolated aspects of green façades, such as their impact on outdoor noise reduction, often focusing on correlations rather than causality. This narrow approach overlooks the broader, interconnected relationships between the numerous variables influenced by green façades, including the interplay between façade-induced biodiversity and both outdoor and indoor soundscapes. This study aims to untangle these interdependencies through a participatory systems thinking approach—a method that has yet to be applied to green façades. It is based on participatory systems thinking workshops involving multidisciplinary topic experts and industry professionals. Workshop findings result in causal loop diagrams, with preliminary results presented here, highlighting relevant variables, feedback loops, and intervention points that characterize the relationships between façades, soundscape, and other domains intertwined in this complex system.