| TOPPAN Edge Payments, Inc. | Tokyo |
| TOPPAN Holdings, Inc. | |
| TOPPERS Project, Inc. | Tokyo |
| TOPS Systems Corporation | Ibaraki |
| TopTech Informatics K.K. | |
| Toray Advanced Computer Solution, Inc. | Tokyo |
| Torex Semiconductor Ltd | Tokyo |
| Torii Pharmaceutical Co., Ltd | |
| Toshiba Corporation | Tokyo |
| Toshiba Electronic Devices & Storage Corporation | Tokyo |
| Toshiba Information Systems (Japan) Corporation | Kanagawa |
| Tosoh Bioscience | |
| Tosoh Corporation | |
| Total Support Co., Ltd | Hyogo |
| Toto Electrical Wire Co., Ltd | Tokyo |
| Tottori University | |
| Tottori University of Environmental Studies | |
| Touchence Co., Ltd | Tokyo |
| Toukei Computer Co., Ltd | Tokyo |
| Touto System Development Co., Ltd | Tokyo |
| TowaElectronics Co., Ltd | Tokyo |
| Towasan Softcreative Co., Ltd | Tokyo |
| Toxsoft | Osaka |
| Toyama College | |
| Toyama Prefectural University | |
| Toyama University of International Studies | |
| Toyo College of Food Technology | |
| Toyo Eiwa Jogakun | |
| Toyo Electric Corporation | |
| Toyo Gakuen | |
| Toyo Label | |
| Toyo System Development Co., Ltd | Tokyo |
| Toyo University | |
| Toyohashi Sozo University | |
| Toyohashi University of Technology | |
| Toyoko Inn IT Solution Co., Ltd | Kanagawa |
| Toyosystem Corporation | Tokyo |
| TOYOTA Connected Corporation | |
| Toyota Industries IT Solutions Co., Ltd | Aichi |
| Toyota Motor Corporation | |
| Toyota Systems Corporation | Aichi |
| Toyota Technological Institute | |
| Toyota Tsusho Systems Corporation | Aichi |
| Toyro, Inc. | |
| Traction Co., Ltd | Tokyo |
| TradeWaltz, Inc. | |
| Transcosmos Partners Co., Ltd | Tokyo |
| TransferNet Corporation | Tokyo |
| Treasury, Inc. | |
| tri-Ace, Inc. | Tokyo |