Diary of a Teenage Girl is a series of Christian young adult novels by Melody Carlson.

It may also refer to:

The Diary of a Teenage Girl: An Account in Words and Pictures, a 2002 graphic novel by Phoebe Gloeckner The Diary of a Teenage Girl, a 2015 American comedy-drama film directed by Marielle Heller, based on the novel The Diary of a Teenage Girl (play), a 2010 play directed by Sarah Cameron Sunde and Rachel Eckerling, based on the novel

See also The Diary of a Young Girl, the diary of Anne Frank