when does derek die in grey's anatomy

Derek Shepherd dies in Season 11, Episode 21 of Grey's Anatomy, titled "How to Save a Life." In this episode, Derek is involved in a car accident after stopping to assist victims of another crash. Although he successfully helps others, Derek himself suffers critical injuries. At the hospital, a delay in ordering a CT scan results in his brain injury being untreated in time. He is declared brain dead, and Meredith Grey, his wife, makes the difficult decision to take him off life support. This episode originally aired on April 23, 2015, and Derek's death marked a significant and emotional turning point in the series.