| Sega Technical Institute | Developer | |
| Sega Toys | DeveloperPublisher | |
| Sega WOW | Developer | |
| Sega Wow | Developer | |
| Sega Yonezawa | Publisher | |
| Sega interActive | Developer | |
| Sega of America | Publisher | |
| Sega of Europe | Developer | |
| Sega-AM1 | Developer | |
| Sega-AM2 | Developer | |
| Sega-AM3 | Developer | |
| Sega-AM4 | Developer | |
| Sega-Gremlin | Publisher | |
| Sega/ | Publisher | |
| SegaEU | Publisher | |
| SegaEU,NA | Publisher | |
| SegaJP | Publisher | |
| SegaJP,KO,NA | Publisher | |
| SegaJP,NA | Publisher | |
| SegaJP/PAL | Publisher | |
| SegaNA | Publisher | |
| SegaNA/EU | Publisher | |
| SegaNA/PAL | Publisher | |
| SegaPAL | Publisher | |
| SegaSoft | DeveloperPublisher | |
| SegaTectoyBR | Publisher | |
| Sega[7] | Publisher | |
| Segedi Inc. | Developer | |
| Sehgel | Developer | |
| Seibu Kaihatsu | DeveloperPublisher | |
| Seibu Kaihatsu / | Publisher | |
| Seif El-Deen Soliman | Developer | |
| Seika | Publisher | |
| Seika Corporation | Publisher | |
| Seika Corporation (NA) | Publisher | |
| Sein Soft | DeveloperPublisher | |
| Sein-Soft | DeveloperPublisher | |
| SeireiART | Developer | |
| Seismic Software NA | Publisher | |
| SeismicNA | Publisher | |
| Seith CG | DeveloperPublisher | |
| SeithCG | DeveloperPublisher | |
| Seityposa | Developer | |
| Seja bem vindo ao Other Level Games | Developer | |
| Sekai Games | Publisher | |
| Sekai Project | Publisher | |
| Sekaibunka Publishing | Publisher | |
| Sekamelica | Developer | |
| Sekii | Developer | |
| Sekruis | Developer | |