Ookami to Koushinryou - Umi wo Wataru Kaze (JP)(Tashiro)
Ookiku Furikabutte - Honto no Ace ni Nareru kamo (J)(6rz)
Open Season (E)(Supremacy)
Open Season (U)(Legacy)
Open Season (E)(Wet 'N' Wild)
Operation - Vietnam (E)(EXiMiUS)
Operation - Vietnam (G)(EXiMiUS)
Operation - Vietnam (U)(XenoPhobia)
Orcs & Elves (U)(XenoPhobia)
Orcs & Elves (E)(sUppLeX)
Ore ga Omae o Mamoru (JP)(Caravan)
Ore no Sentoki (J)(SCZ)
Orient Quest (E)(G)(PUSSYCAT)
Original Frisbee Disc Sports - Ultimate & Golf (U)(EXiMiUS)
Original Frisbee Disc Sports - Ultimate & Golf (E)(sUppLeX)
Original Story from Fairy Tail - Gekitotsu! Kardia Daiseidou (J)
Osawari Tantei - Ozawa Rina (J)(SCZ)
Oscar the Balloonist - Animalistic Adventures (E)
Oshaberi Oumu (JP)(High Road)
Oshare Majo - Love and Berry (J)(WRG)
Oshare ni Koi Shite 2 Plus (JP)
Oshare Princess - Oshare ni Koishite 2 (JP)(BAHAMUT)
Oshare Princess DS - Oshare ni Koishite! (J)(WRG)
Oshiri Kajiri Mushi no Rhythm Lesson DS - Kawai Ongaku Kyoushitsu Kanshuu (J)(Independent)
Osu! Tatakae! Ouendan! (J)(ProjectG)
Othello de Othello DS (J)(NEET)
Oto o Tsunagou! Gunpey Reverse (J)(Legacy)
Otogi Juushi Akazukin (J)(WRG)
Otometeki Koi Kakumei - Love Revo!! DS (J)(6rz)
Otona no DS Golf (J)(WRG)
