A film version of '' The Diary of a Teenage Girl '' premiered at the 2015 Sundance Film Festival . The film was acquired by Sony Pictures Classics at the festival . Adapted and directed by Marielle Heller , it is based on Heller 's earlier stage adaptation . The film stars Alexander Skarsgård as Monroe , Kristen Wiig as Charlotte , and Bel Powley as the main character , Minnie Goetze . Heller developed the script at the Sundance Institute 's Sundance Feature Film Program Lab . The film won " Best First Feature " at the 2016 Spirit Awards
2015 Sundance Film Festival
2015 Sundance Film Festival
Phoebe Gloeckner