- O.W. Gurley
- Ocean Speaks
- Odell Beckham Jr.
- Of Thee I Sing: Read & Listen Edition
- Old Dog Tray: Stephen Foster and His Dogs
- Old Hickory:Andrew Jackson and the American People
- Olga Korbut: Gymnastics Trailblazer
- On Our Way to Oyster Bay
- On the Court with ... Kobe Bryant
- On the Court with ... Shaquille O'Neal
- On the Court with...Venus and Serena Williams
- On the field with ... Alex Rodriguez
- On the Field with...Peyton and Eli Manning
- On the Halfpipe with...Tony Hawk
- On the Job Filmmakers: Adding and Subtracting Mixed Numbers
- On the Job: Filmmakers: Adding and Subtracting Mixed Numbers: Read-along ebook
- On the Track with...Jeff Gordon
- One Direction: The Official Annual 2015
- One Direction: The Official Annual 2016
- One Direction: Where We Are Now
- One Hundred Reasons To Hope
- One Hundred Steps: The Story of Captain Sir Tom Moore
- One Life: Young Readers Edition
- One Plastic Bag