Marianne Nölle (born 1938) is a German serial killer from Cologne. She was sentenced to life imprisonment in 1993 for seven murders.
Nölle was a nurse and between 1984 and 1992 killed patients in her care using Truxal. Police think she killed a total of 17 and attempted 18 other murders, but she was only convicted of seven. She has never confessed to her crimes.