List of free, open source operating systems

Updated: April 27, 2026

Please note that in some cases, such as with Qubes and Asahi Linux, they are technically "distros" of Linux. However, given their extreme departure from what normally constitutes a Linux distribution, I've listed them here. And allow me to say I have a ton of respect for said projects.

  1. OpenBSD
  2. Linux
  3. FreeBSD
  4. NetBSD
  5. Dragonfly BSD
  6. Qubes OS
  7. Asahi Linux
  8. Haiku
  9. Redox
  10. Serenity
  11. ReactOS
  12. AROS
  13. FreeDOS
  14. BASIC-DOS
  15. Blog series: Writing an OS in Rust
  16. skiftOS
  17. RetrOS-32
  18. Tock
  19. Hubris
  20. Essence
  21. Subgraph OS
  22. Ares
  23. osv.io
  24. axle OS
  25. hk
  26. Snowdrop OS
  27. Astral
  28. vekos
  29. Essence
  30. Barrelfish
  31. ToaruOS
  32. MyraOS
  33. Mezzano
  34. House
  35. Minoca OS
  36. Kerla
  37. SOS
  38. PowerNex
  39. Interim OS
  40. KolibriOS
  41. MINIX
  42. RISC OS
  43. HelenOS
  44. GeckOS/A65 V2.0
  45. GNU Hurd
  46. Plan 9
  47. Harvey
  48. illumos
  49. AquilaOS
  50. NuttX
  51. Sculpt
  52. Biscuit
  53. Xv6