- O amigo de Darwin
- O is for Oklahoma
- O mar que banha a ilha de Goré
- O mundo perdido
- O Mário que não é de Andrade
- O peso da luz
- O segredo do ídolo de barro
- O Smoku spod Wawelu
- Ociee and Ben Nash, the Asheville Adventure
- Odisseia Olímpica
- Odysseus pojke
- Ohne den Vater
- Old Rock (is not boring)
- Olka and Her Blue Parasol
- Olka and Her Blue Parasol
- Olka and Her Blue Parasol (Yiddish and English)
- Oma, ich kann deine Geschichten schon lesen
- On the Duty of Civil Disobedience
- On The Wings of Heroes
- On Track for Treasure
- Once Upon a Time Long, Long Ago
- Once Upon Another Time
- Onde øjne
- Ondinas (Serie Elementales)
- One Last Word
- One Love, One Heart
- One Small Blue Bead
- One Today
- Onkel Toms Hütte (Illustrierte Ausgabe)
- Onyx
- Opal Dreaming: The Marble Horses
- Orphan of Destiny
- Orphan Train Riders Charles' Christmas Gift
- Oscar's American Dream
- Oskar and the Eight Blessings
- Otto of the Silver Hand
- Otur i borgen
- Our Other Lives
- Our Trip to the Presidential Inauguration
- Outback Outlaw