| Name | License | Kernel type | Kernel programming language | Kernel thread support | OS family | Oldest non-EOL version | Forks |
| Linux | | Monolithic with modules | C | 1:1 | Unix-like | 3.16 | elks |
| FreeBSD | | Monolithic with modules | C | 1:1 | BSD, Unix-like | 11 | DragonFly BSD |
| OpenBSD | | Monolithic | C | 1:1 | BSD, Unix-like | 6.4 | MirOS |
| NetBSD | | Monolithic with modules | C | 1:1 | BSD, Unix-like | 7.0 | OpenBSD |
| DragonFly BSD | | Hybrid | C | 1:1 | BSD, Unix-like | | |
| OpenSolaris, illumos | | Monolithic with modules | C | 1:1, M:N | Unix | | |
| Darwin, OpenDarwin | | Hybrid | C, C++ | 1:1 | BSD, Unix, Unix-like, OS X | | |
| MINIX | | Microkernel | C | | Unix-like | | |
| RedoxOS | | Microkernel | Rust | | Unix-like | | |
| FreeRTOS | | RTOS | C | | RTOS | | |
| FreeDOS | | Monolithic | C | | DOS | 1.1 | |
| Genode | | Microkernel | C++ | 1:1 | Genode | | |
| Haiku | | Hybrid | C, C++ | | BeOS | | |
| House | | | Haskell | | own/original | | |
| KolibriOS | | Monolithic | ASM | | MenuetOS | | |
| MenuetOS | | Monolithic | ASM | | own/original | | KolibriOS |
| GNU | | or Monolithic | C | 1:1 | Unix-like | 2.4 on Linux-libre kernel | Linux |
| ReactOS | | Hybrid | C, C++ | | Windows-like | | |
| RISC OS | | Monolithic | ARM assembly | | RISC OS | | RISC OS 6 |
| L4, Fiasco, | | Microkernel | C++ | | L4 | | |
| Plan 9 | | Hybrid | C | 1:1, 1:M Cothread style. | own, Unix informed | | Inferno, Plan B |
| AROS | | Exokernel | C | | AmigaOS | | |
| Syllable | | Monolithic with modules | C, C++ | 1:1 | Unix-like, BeOS, AmigaOS, POSIX | | |
| Inferno | | | C | | Plan 9 | | OzInferno |
| NuttX | | RTOS | C | | RTOS | | |
| eCos | | RTOS | C, C++ | | RTOS | | |
| RTEMS | | RTOS | C and ASM with native support for other languages including C++ and Ada | POSIX, RTEID/ORKID, uITRON | RTOS | 4.7.1 | |
| HelenOS | | Microkernel | C | M:N | own/original | | |
| E/OS | | Monolithic | ASM, C | 1:1 | BeOS, Unix-like | | |
| TempleOS | | Monolithic | HolyC, C, C++ | | Commodore 64-like | | |
| Name | License | Kernel type | Kernel programming language | Kernel thread support | OS family | Oldest non-EOL version | Forks |
