Aim: To study the effect of naturalistic light, programmed to replicate the spectrum distribution of natural light from dusk to dawn, on agitation measured with a Cohen-Mansfield Agitation Inventory–inspired score of nursing home residents with dementia. Background: Though the effects of different types of light on the sleep-wake patterns of senior adults and people with dementia have been examined in several studies, the effects of naturalistic light systems, as a possible nonpharmacological intervention to improve sleep and reduce agitation, have yet to be extensively evaluated due to the relative novelty of the technology. Methods: The study was designed as a 6-month pilot study of a prospective interventional longitudinal cohort study, with five participants recruited from a single department of a Danish nursing home. The effect of naturalistic lighting on agitation-associated behaviors was recorded over a 3-day period pre- and postintervention. Results: An overall 71.2% reduction in the frequency of agitation-associated behaviors was recorded, with the frequency of some behaviors even reduced by 100%. Conclusions: This pilot study estimates that naturalistic lighting may be a promising nonpharmacological intervention to improve the overall agitation of nursing home residents with dementia, with a possible added benefit of an improved work environment for the staff. This study, therefore, finds indication for the performance of a randomized controlled trial with the same intervention and a larger cohort.