• Oitsumerarete
  
• Okaasan te Nan Darou?
  
• Okaasan te Nan Darou
  (2004 Summer Version)
  
• Omoidashite Anata wo
  
• Onna Kaizoku no Sakusen
  
• Onna Kaizoku no Sakusen
  (2004 Summer Version)
  
• Onna no Ko no Shinsou
  
• Onna no Ronsou
  
• Orleans no Sei Senshi
  
• Orleans no Sei Senshi
  ~Uranus - Neptune no Uragiri~
  
• Over the Moon
  
• Overture ~ Suisei Coatl no Hibou