Happening won the Golden Lion Photo: Courtesy of Venice Film Festival
The film, which is set in the 1960s, follows a woman who wants to end her pregnancy in order to continue her studies.
Accepting the award, Diwan said: "I did this movie with anger, with desire, with my belly, my guts, my heart and my head,"
The jury, headed by Parasite director Boon Jong Ho, gave the Grand Jury Prize to Paolo Sorrentino's autobiographical Hand Of God.
On a good night for female talent in general, Maggie Gyllenhaal picked up the Best Screenplay Award for her debut The Lost Daughter and Jane Campion was named Best Director for her western The Power Of The Dog, starring Benedict Cumberbatch and Kirsten Dunst.
Audrey Diwan receives the Golden Lion for Happening Photo: La Bienalle De Venezia
Acting awards went to Penelope Cruz for her role in Pedro Almodovar's Parallel Mothers and John Arcilla for Erik Matti's On The Job 2: The Missing 8.
The full list of award winners is below:
Golden Lion for Best Film
Happening, dir. Audrey Diwan
Grand Jury Prize
The Hand of God, dir. Paolo Sorrentino
Jane Campion, for The Power of the Dog
John Arcilla for On The Job: The Missing 8
Penelope Cruz for Parallel Mothers
Maggie Gyllenhaal for The Lost Daughter
Best Young Actor
Filippo Scotti for The Hand of God
Special Jury Prize
Il Buco, dir. Michelangelo Frammartino
Lion of the Future for Best Debut Film
Imaculat, dir. Monica Stan, George Chiper-Lillemark
Orizzonti Section Prizes
Pilgrims, dir. Laurynas Bareisa
Eric Gravel for Full Time
Special Jury Prize
The Great Movement dir. Kiro Russo
Piseth Chhun for White Building
Laure Calamy for Full Time
Peter Kerekes, Ivan Ostrochovsky for 107 Mothers
Best Short Film
Los Huesos, dir. Cristobal Leon, Joaquin Cocina
The Blind Man Who Didn’t Want To See The Titanic, dir. Teemu Nikki
Venice VR Expanded
Best VR Story
End of Night, dir. David Adler
Best VR Experience
Le Bal De Paris, dir. Blanca Lee.
Best VR Work
Goliath Playing With Reality, dir. Barry Gene Murphy, May Abdalla