- O.W. Gurley
- Ocean Speaks
- Of Thee I Sing
- Old Dog Tray: Stephen Foster and His Dogs
- Old Hickory:Andrew Jackson and the American People
- Olga Korbut: Gymnastics Trailblazer
- Olympic Dream
- Omero era un figo
- On a Beam of Light
- On Our Way to Oyster Bay
- On the Bike with...Lance Armstrong
- On the Court with ... Jennifer Capriati
- On the Court With... Hakeem Olajuwon
- On the Court with...Dwight Howard
- On the Court with...Kevin Durant
- On the Court with...LeBron James
- On the Court with...Stephen Curry
- On the Field with ... Julie Foudy
- On the Field with ... Terrell Davis
- On the Field with...Derek Jeter
- On the Field with...Megan Rapinoe, Alex Morgan, Carli Lloyd, and Mallory Pugh
- On the Field with...Tom Brady
- On the Ice with...Mario Lemieux
- On the Ice with...Tara Lapinski
- On the Job Filmmakers: Adding and Subtracting Mixed Numbers
- On the Job: Filmmakers: Adding and Subtracting Mixed Numbers: Read-along ebook
- On the Mound with ... Curt Schilling
- On Wings of Words
- One Day in Wonderland
- One Direction: A Year with One Direction
- One Direction: Behind the Scenes
- One Direction: Meet One Direction
- One Direction: The Official Annual 2014
- One Direction: The Official Annual 2015
- One Direction: The Official Annual 2016
- One Hundred Reasons To Hope
- One Hundred Steps: The Story of Captain Sir Tom Moore
- One Life: Young Readers Edition
- Only Margaret
- Oorlog in inkt
- Opal Lee and What It Means to Be Free
- Opening the Road
- Oscar Peterson
- Our House Is on Fire
- Our Little Mushroom
- Our Queen Elizabeth
- Our World
- Out of The Blue, Young Reader's Edition
- Out of the Woods
- Overview of the Korean War
- Overview of the Persian Gulf War, 1990