I-FreeBSD iwuhlelo olusebenzayo olufana nomthombo ovulekile lwe-Unix olusuka ku-Berkeley Software Distribution (BSD), olwalusekelwe ku-Research Unix. Inguqulo yokuqala ye-FreeBSD yakhululwa ngo-1993. Ngo-2005, i-FreeBSD kwakuyisistimu yokusebenza ye-BSD yomthombo ovulekile edume kakhulu, ebalwa ngaphezu kwezingxenye ezintathu kwezine zazo zonke izinhlelo ze-BSD ezifakiwe nezivunyelwe ngokuvunyelwa. I-FreeBSD inokufana ne-Linux, enomehluko omkhulu kabili kububanzi kanye nokunikezwa kwelayisensi: I-FreeBSD igcina uhlelo oluphelele, okungukuthi iphrojekthi iletha i-kernel, abashayeli bedivayisi, izinsiza ze-userland, kanye nemibhalo, ngokuphambene ne-Linux eletha kuphela i-kernel nabashayeli, futhi ithembele kubantu besithathu ngesofthiwe yesistimu; Ikhodi yomthombo ye-FreeBSD ngokuvamile ikhishwa ngaphansi kwelayisensi ye-BSD evumelekile, ngokuphambene ne-copyleft GPL esetshenziswa yi-Linux. Iphrojekthi ye-FreeBSD ihlanganisa ithimba lezokuphepha eliqondise wonke ama-software athunyelwa ngokusatshalaliswa kwesisekelo. Izinhlobonhlobo zezinhlelo zokusebenza ezengeziwe zezinkampani zangaphandle zingase zifakwe kusuka kumaphakheji kanambambili kusetshenziswa isistimu yokuphatha iphakheji ye-pkg noma kusuka kumthombo ngezimbobo ze-FreeBSD,[6] noma ngokuhlanganisa ikhodi yomthombo mathupha. Iningi le-codebase ye-FreeBSD seliyingxenye ebalulekile yezinye izinhlelo zokusebenza ezifana ne-Darwin (isisekelo se-macOS, i-iOS, i-iPadOS, i-watchOS, ne-tvOS), i-TrueNAS (umthombo ovulekile wesistimu yokusebenza ye-NAS/SAN), kanye nesofthiwe yesistimu ye-PlayStation 3 kanye ne-PlayStation 4 game consoles.