| Letters, Inc. | |
| Levechy, Inc. | |
| LiberoThera Co., Ltd | Tokyo |
| Life Diagnostics, Inc. | |
| Lifestyle Design Co., Ltd | Tokyo |
| Lifetime Ventures | |
| LIG, Inc. | |
| Light, Inc. | Tokyo |
| LightStone Corporation | Tokyo |
| LINE Corporation | Tokyo |
| Line Seiki Co., Ltd | Tokyo |
| LINET Co., Ltd | Tokyo |
| Linical | |
| Linkclub | Tokyo |
| LinkPlan | |
| LinkShare Japan Co., Ltd | Tokyo |
| Linkweb | Tokyo |
| Linné Corporation | Tokyo |
| Linux Professional Institute of Japan | Tokyo |
| Linuxmania.jp | Tokyo |
| LINX Corporation | Tokyo |
| Liquid Co., Ltd | Tokyo |
| Litec Corporation | Kyoto |
| Little Studios Co., Ltd | Tokyo |
| LittleSoft Corporation | Tokyo |
| Living Robot Co., Ltd | Tokyo |
| Livt Co., Ltd | Tokyo |
| LocationMind Co., Ltd | |
| LOGIC Co., Ltd | Tokyo |
| LogicVein, Inc. | |
| Logitec INA Solutions Co., Ltd | Tokyo |
| Logly Co., Ltd | Tokyo |
| Logosware Co., Ltd | Tokyo |
| LogoVista | Tokyo |
| Lolipop! | Tokyo |
| Loops, Inc. | Tokyo |
| LPixel, Inc. | |
| LSI Technology Co., Ltd | |
| LUCA Science Co., Ltd | Tokyo |
| Lucid Software Co., Ltd | Tokyo |
| Lunascape Phoebe | Tokyo |
| Luxman Corporation | Osaka |
| Luxna Biotech Co., Ltd | Osaka |
| LY Corporation | |
| M&S Systems Designers Co., Ltd | Tokyo |
| M-Tech Co., Ltd | |
| M2soft Japan Co., Ltd | Tokyo |
| Mabuchi S&T Co., Ltd | Nagano |
| mabWare | Tokyo |
| Macbee Planet, Inc. | |