| VirtuOS | — | — | — |
| Visi On | VisiCorp | — | — |
| VisionOS 2 | Apple Inc. | — | — |
| VisionOS 26 | — | — | — |
| VisionOS 27 | — | — | — |
| Visopsys | — | — | GNU General Public License, version 2.0 |
| VM | IBM | — | — |
| VM-CP | IBM | — | — |
| VortexBox | — | — | — |
| VOS3 | Hitachi | — | — |
| VP/CSS | IBM, National CSS | — | — |
| VPS/VM | Boston University | — | — |
| VS/9 | UNIVAC | — | — |
| VSE | IBM | — | — |
| Vw.os | Volkswagen Group | — | — |
| VyOS | — | — | GNU General Public License, version 2.0 |
| WAITS | Stanford Artificial Intelligence Laboratory | — | — |
| Wang VSOS | Wang Laboratories | — | — |
| WatchOS 1 | Apple Inc. | 2015 | Apple Public Source License |
| WatchOS 10 | Apple Inc. | — | — |
| WatchOS 11 | Apple Inc. | 2024 | — |
| WatchOS 2 | Apple Inc. | 2015 | Apple Public Source License |
| WatchOS 3 | Apple Inc. | 2016 | Apple Public Source License |
| WatchOS 4 | — | 2017 | Apple Public Source License |
| WatchOS 5 | — | 2018 | Apple Public Source License |
| WatchOS 6 | Apple Inc. | — | — |
| WatchOS 7 | Apple Inc. | — | — |
| WatchOS 8 | Apple Inc. | — | — |
| WatchOS 9 | Apple Inc. | — | — |
| Webconverger | — | — | — |
| WebOS | LG Electronics | — | GNU General Public License, Apache License |
| WebOS Open Source Edition | — | — | Apache Software License 2.0 |
| Whitix | — | — | — |
| Wii system software | Nintendo | 2006 | — |
| Wii U system software | Nintendo | — | — |
| Windows 1.0 | Microsoft, NEC | 1985 | end-user license agreement |
| Windows 1.04 | Microsoft | 1987 | — |
| Windows 10 | Microsoft | 2015 | shareware, Microsoft Software Assurance, Azure Dev Tools for Teaching |
| Windows 10 S | Microsoft | — | — |
| Windows 10 Version 1507 | Microsoft | 2015 | — |
| Windows 10 Version 1511 | Microsoft | 2015 | — |
| Windows 10 Version 1607 | Microsoft | — | — |
| Windows 10 Version 1703 | Microsoft | — | — |
| Windows 10 Version 1709 | Microsoft | 2017 | — |
| Windows 10 Version 1803 | Microsoft | — | — |
| Windows 10 Version 1809 | Microsoft | 2018 | — |
| Windows 10 Version 1903 | Microsoft | 2019 | — |
| Windows 10 Version 1909 | Microsoft | — | — |