| H | Hydrogen |
| H2DI | Hydrogen Direct Injection |
| HAC | Hill Assist Control |
| HBA | Hydraulic Brake Assist |
| HC | Hydrocarbons |
| HCCI | Homogeneous Charge Compression Ignition |
| HCFC | Hydrochlorofluorocarbon |
| HCM | Heating Control Module |
| HCV | Heavy Commercial Vehicle |
| HD | Heavy Duty (vehicle or lubricant) |
| HDD | Heavy Duty Diesel |
| HDDO | Heavy Duty Diesel Oil |
| HDDT | Heavy Duty Diesel Trucks |
| HDE | Heavy Duty Engine |
| HDGT | Heavy Duty Gasoline Trucks |
| HDMO | Heavy Duty Diesel Engine Oil |
| HDT | Heavy Duty Trucks |
| HDVIP | Heavy Duty Vehicle Inspection Program |
| HEFCAD | High Energy Friction Characteristics And Durability |
| HEPS | Hydraulic Electric Power Steering |
| HEUI | Hydraulically operated, Electronically controlled Unit Injectors |
| HEV | Hybrid Electric Vehicle |
| HFC | Hydrofluorocarbon |
| HFFI | Heavy Fuel Flow Improver |
| HFO | Heavy Fuel Oil |
| HF-O/1/2 | Hydraulic Fluid specifications (Denison) |
| HFRR | High Frequency Reciprocating Rig test |
| HHDV | Heavy-Heavy Diesel Vehicle |
| HID | High Intensity Discharge |
| HIS | Horizontal Impact Sensor |
| HLDT | Heavy Light-Duty Truck |
| HMI | Human Machine Interface |
| HO2S | Heated Oxygen Sensor |
| HP | Horsepower |
| HPDI | High Pressure Direct Injection |
| HPL | High Pressure Liquid |
| HPP | High Pressure Pump |
| HSA | Head Side Airbag |
| HSC | High Swirl Combustion |
| HSCDS | High-Sensitivity Collision Detection System |
| HSDI | High Speed Direct Injection (diesel engine) |
| HSEA | High Solar Energy Absorbing (glass) |
| HTCM | Heating-ventilation-air-conditioning Thermal Control Module |
| HTHS | High Temperature High Shear (viscosity) |
| HTHSRV | High Temperature High Shear Rate Viscosity |
| HUD | Heads Up Display |
| HVAC | Heater-Vent-Air Conditioning |
| HVACM | Heater-Vent-Air Conditioning Module |
| HVI | High Viscosity Index |
| HW | Heated Windshield |
| HWBF | High Water-Based Fluid |
| HYPAS | Hydraulic Power Assisted Steering |
| Hz | Hertz |
