The initial M998 HMMWV series consists of the following models:
M998 Cargo/Troop Carrier Vehicle (in various configurations)
M1038 Cargo/Troop Carrier Vehicle with winch
M966 TOW Missile Platform with basic armor
M1036 TOW Missile Platform with basic armor with winch
M1045 TOW Missile Platform with supplemental armor
M1046 TOW Missile Platform with supplemental armor with winch
M1025 Armament Carrier with basic armor
M1026 Armament Carrier with basic armor with winch
M1043 Armament Carrier with supplemental armor
M1044 Armament Carrier with supplemental armor with winch
M977 Maxi-ambulance for four stretchers with basic armor
M996 Mini-ambulance for two stretchers with basic armor
M1035 Ambulance with soft top for two stretchers
M1037 Shelter Carrier
M1042 Shelter Carrier with winch
M1069 Prime Mover (Based on the M1097 HHV for towing the M102/M119 105mm Light Gun)
M1097 HHV (Heavy Hummer Variant)
Avenger Air Defense Missile System (based on the M1037 Shelter Carrier)

The M998A2 series comprises six different models all initially produced without a winch.
M1097A2 HHV is the base platform for cargo and troop carriers.
M1025A2 Armament Carrier with basic armor
M1043A2 Armament Carrier with supplemental armor
M1045A2 TOW Missile Platform with supplemental armor
M977A2 Maxi-Ambulance for four stretchers with basic armor
M1035A2 Ambulance with soft top for two stretchers

A new model M1109 Up-armored HMMWV based on the M1097A1 HHV (only 159 produced for the US Army) followed by the M1114 Up-armored HMMWV based on the M1113 Expanded Capacity Vehicle (ECV) chassis. The M1114 differs significantly from the A2 vehicles in having and extended nose and additional body and roof armor able to protect against overhead 155mm shell bursts and 7.62mm fire at a standoff on 100m. Additional grills are fitted on the left rear panels for the air-conditioning system as well as the four roof mounted smoke grenade launchers, these vehicles have seen service in the Kosovo as well as Operation Iraqi Freedom and will eventually replace the M1025/26 series of Armament Carriers.