The aim of this study is to examine the association between modifiable structural and process factors and self-reported as well as observed pain in Swiss residential long-term care residents. Sub-study of a multicentre cross-sectional survey. Institution, unit, and staff data were collected from September 2018 to October 2019 in 118 residential long-term care institutions in Switzerland's German- and French-speaking regions using paper questionnaires. Resident data were exported during the same period from routine data sets. In this study, 6213 residents from 86 residential long-term care institutions were included. Modifiable structural factors such as institutions having access to geriatricians, nursing experts and a palliative care team, the presence of a pain guideline on the unit and good teamwork among care workers were associated to less pain in residents. It is possible for residential long-term care institutions to improve pain in residents and to optimise the quality of care by providing access to geriatricians, nursing experts and a palliative care team, working with a pain guideline and fostering teamwork. Residential long-term care institutions can modify and implement modifiable structural factors which can reduce pain in residents to optimise residents' quality of life and quality of care. Improved pain management in residential long-term care institutions can lead to optimised quality of care and quality of life for individual residents. STROBE checklist. No patient or public contribution.