List of free, open source operating systems

Updated: March 16, 2021

  1. OpenBSD
  2. Linux
  3. FreeBSD
  4. NetBSD
  5. Dragonfly BSD
  6. Qubes OS
  7. Haiku
  8. Redox
  9. ReactOS
  10. AROS
  11. FreeDOS
  12. BASIC-DOS
  13. Blog series: Writing an OS in Rust
  14. skiftOS
  15. Tock
  16. Subgraph OS
  17. osv.io
  18. Barrelfish
  19. ToaruOS
  20. Mezzano
  21. House
  22. Minoca OS
  23. SOS
  24. PowerNex
  25. Interim OS
  26. KolibriOS
  27. MINIX
  28. RISC OS
  29. HelenOS
  30. GeckOS/A65 V2.0
  31. Serenity
  32. GNU Hurd
  33. Plan 9
  34. Harvey
  35. illumos
  36. AquilaOS
  37. Sculpt
  38. Biscuit
  39. Xv6