Editing List of companies of Japan (section)

==O==
{| class="wikitable"
|-
! English
! Japanese
! [[Rōmaji]]
! [[Tokyo Stock Exchange|TSE]]
|-
| [[Obayashi Corporation]]
| [[:ja:大林組|株式会社大林組]]
| ''Kabushiki-gaisha Ōbayashi Gumi''
| {{Tyo1|1802}}
|-
| [[Odakyu Electric Railway]]
| [[:ja:小田急電鉄|小田急電鉄株式会社]]
| ''Odakyū Dentetsu Kabushiki-gaisha''
| {{Tyo1|9007}}
|-
| [[Ohara Corporation]]
| [[:ja:オハラ (ガラスメーカー)|株式会社オハラ]]
| ''Kabushiki-gaisha Ohara''
| {{Tyo1|5218}}
|-
| [[Ohto]]
| [[:ja:オート (文具)|オート株式会社]]
| ''Ōto kabushiki gaisha''
|
|-
| [[Oji Paper Company]]
| [[:ja:王子製紙|王子製紙株式会社]]
| ''Ōji Seishi Kabushiki-gaisha''
| {{Tyo1|3861}}
|-
| [[Oki Electric Industry]]
| [[:ja:沖電気工業|沖電気工業株式会社]]
| ''Oki Denki Kōgyō Kabushiki-gaisha''
| {{Tyo1|6703}}
|-
| [[Okuma Corporation]]
| [[:ja:オークマ|オークマ株式会社]]
| ''Ōkuma Kabushiki-gaisha''
| {{Tyo1|6103}}
|-
| [[Okura Hotels]]
| [[:ja:ホテルオークラ|ホテルオークラ]]
| 
|
|-
| [[Olfa|Olfa Corporation]]
| [[:ja:オルファ|オルファ株式会社]]
| ''Orufa Kabushiki-gaisha''
|
|-
| [[Olympus company|Olympus]]
| [[:ja:オリンパス|オリンパス株式会社]]
| ''Orinpasu Kabushiki-gaisha''
| {{Tyo1|7733}}
|-
| [[Omron]]
| [[:ja:オムロン|オムロン株式会社]]
| ''Omuron Kabushiki-gaisha''
| {{Tyo1|6645}}
|-
| [[Onkyo]]
| [[:ja:オンキヨー|オンキヨー株式会社]]
| ''Onkyō Kabushiki-gaisha''
| {{Tyo1|6729}}
|-
| [[Ono Pharmaceutical]]
| [[:ja:小野薬品工業|小野薬品工業株式会社]]
| ''Ono Yakuhin Kōgyō Kabushiki-gaisha''
| {{Tyo1|4528}}
|-
| [[OPA Co., Ltd.]]
| [[:ja:OPA|株式会社OPA]]
| ''Kabushiki-gaisha OPA''
| 
|-
| [[Orient Watch|Orient]]
| [[:ja:オリエント時計|オリエント時計]]
| ''Oriento Tokei''
|
|-
| [[The Oriental Land Company]]
| [[:ja:オリエンタルランド|株式会社オリエンタルランド]]
| ''Kabushikigaisha Orientaru Rando''
| {{Tyo1|4661}}
|-
| [[Orion Breweries]]
| [[:ja:オリオンビール|オリオンビール株式会社]]
| ''Orion Bīru Kabushiki-gaisha''
|
|-
| [[Orix]]
| [[:ja:オリックス (企業)|オリックス株式会社]]
| ''Orikkusu Kabushiki-gaisha''
| {{Tyo1|8591}}
|-
| [[O.S. Engines]]
| [[:ja:小川精機|小川精機株式会社]]
| ''Ogawa Shigeo Kabushiki-gaisha''
| 
|-
| [[Osaka Gas]]
| [[:ja:大阪瓦斯|大阪瓦斯株式会社]]
| ''Ōsaka Gasu Kabushiki-gaisha''
| {{Tyo1|9532}}
|-
| [[Osaka Titanium Technologies]]
| [[:ja:大阪チタニウムテクノロジーズ|株式会社大阪チタニウムテクノロジーズ]]
| ''Ōsaka Chitaniumu Tekunorojīzu Kabushiki-gaisha''
| {{Tyo1|5726}}
|-
| [[Otsuka Pharmaceutical Co.]]
| [[:ja:大塚製薬|大塚製薬株式会社]]
| ''Ōtsuka Seiyaku Kabushiki-gaisha''
| {{Tyo1|4578}}
|}