AbstractBackground Light therapy (LT) for Seasonal Affective Disorders (SAD) has been a well-known and effective treatment for 40 years. The psychiatric university clinic of Groningen, the Netherlands was an early adopter and started research and treatment of SAD in 1987. Research projects on mechanisms, the role of the circadian system, treatment optimization, and investigating new areas for the effects of light treatment have been carried out ever since, leading to a widespread interest across the country.Objective To provide an overview and description of the historical development of LT for mental disorders in the Netherlands.Methods A non-systematic, review of research on light treatment for mental problems in the Netherlands, published since 1987 was conducted.Results The fields of LT and chronotherapy are strongly based in the scientific interests of both chrono-biologists and therapists in the Netherlands. LT has shown effectiveness in treating mood disorders. Likewise, results for other mental disorders have shown some promise, but so far, the outcomes are not always unequivocal and have not always been based on robust data. Ongoing research is discussed.Conclusions LT, and in addition exposure to the right light at the right time is an important issue in mental health. Over the past 3 decades research on light and LT in the Netherlands has become well established and is still growing.