Two expansion packs by outside developer Gearbox Software have been released for the PC version: Half-Life: Opposing Force (1999) and Half-Life: Blue Shift (2001).
Mõlemad kahest Gearbox Software'i poolt arendatud lisapakist on ilmunud ka PC-versioonile, nendeks on: "Half-Life: Opposing Force" (1999) ja "Half-Life: Blue Shift" (2001).