The Moth Diaries is a 2011 Irish-Canadian horror film directed by Mary Harron and based on a 2002 novel of the same name by Rachel Klein.
At an exclusive boarding school for girls, Rebecca (Sarah Bolger), a sixteen-year-old teenage girl, records her most intimate thoughts in a diary. Two years ago, Rebecca's father, a gloomy poet, committed suicide by slitting his wrists. Her mother transferred Rebecca to the school, hoping to help her daughter escape the dark memories of her father's death. With the help of her best friend and roommate, Lucy (Sarah Gadon), and many other girls, Rebecca soon recovered.