- The Day That Lasted 21 Years
- O. Henry a Life in Stories
- Objectified
- Obscene: A Portrait of Barney Rosset and Grove Press
- OC87: The Obsessive Compulsive, Major Depression, Bipolar, Asperger's Movie
- Occupation: Fighter
- Occupy Love
- Occupy Unmasked
- Ocean Wonders: Inside the Monterey Bay Aquarium
- October Country
- Of By For
- Of Dolls & Murder
- Of Two Minds
- Off and Running
- Off Label
- Off the Grid With Les Stroud
- Off the Grid: Life On the Mesa
- Off the Rez
- Office Tigers
- Oil City Confidential
- Okie Noodling
- Oldies but Goldies
- Oma & Bella
- On Any Sunday
- On Any Sunday Motocross, Malcolm & More
- On Any Sunday Revisited
- On Coal River
- The Tightrope of Life (On ne mourra pas d'en parler)
- On the Bowery
- On the Pipe 2 - Still Smokin
- On the Pipe 5
- Once I Was a Champion
- Once in a Blue Moon
- Once in a Lifetime: The Extraordinary Story of the New York Cosmos
- Once Upon a Wheel
- Onde nostre: Guarda dove ti ho portato
- One Bad Cat: The Reverend Albert Wagner Story
- One Big Holiday
- One Bright Shining Moment
- One Crazy Ride
- One Day on Earth
- One Direction
- One Direction: All the Way to the Top
- One Direction: Clevver's Ultimate Fan Guide
- One Direction: Going Our Way
- One Direction: Reaching for the Stars Part 2 - The Next Chapter
- One Direction: This Is Us
- One Life (2013)
- One Love: The Game. The Life.
- One Lucky Elephant
- One Man: Mandela
- One Mile Away
- One More - A Definitive History of UK Clubbing 1988 - 2008
- One Night in Turin
- One Peace At a Time
- One Six Right
- One Touch
- One Track Heart: The Story of Krishna Das
- One Wall: Kings of Coney Island
- One Week in Plum Village
- One Week Job
- One: The Movie
- Only the Strong Survive
- Only the Young
- Openings: The Search for Harry
- Operation Enduring Freedom: America Fights Back
- Operation Homecoming
- Operation Last Patrol
- Orgasm Inc.
- Orphans of Apollo
- Orwell Rolls in His Grave
- OT: Our Town
- Our Brand Is Crisis
- Our City Dreams
- Our Nixon
- Our Summer in Tehran
- Our Vinyl Weighs A Ton: This Is Stones Throw Records
- OUT in the line-up
- Out In the Silence
- Out in the Silence: Extended Edition
- Out Late
- Out of Balance
- Out of the Clear Blue Sky
- Outbreak: Anatomy of a Plague
- Outrage (2009)
- Outside In - The Story of Art in the Streets
- Over the Edge: Motorcycle Mayhem X
- Overdose
- Owning the Weather
- Oxyana