The aim of this cross-sectional study was to explore the role of nursing staff in residents’ activities. Nursing home residents (n = 723) were observed in their wards, randomly five times for one minute between 7 a.m. and 11 p.m. Resident's (in)activity and the role of nursing staff or others in this activity were recorded. Roles were defined as ‘taking over the activity’, ‘giving support’, or ‘supervision’. Nurse observers were interviewed to obtain insight into their observation-experiences. Residents were observed in activities of daily living in 31% of all 3282 observations, and inactive in 57%. Nursing staff provided support in 51% of the observations and took over activities in 45%; supervision was rarely observed (4%). Nurse observers who knew the residents reported that a large part of activities were taken over unnecessarily. Based on these results, nursing staff are recommended to provide more supervision and support to optimize residents’ activities and independence.