| Acronym | Meaning |
| HPI | Hydrocarbon Processing Industry |
| HPI | Hazard Potential Index |
| HPIAC | High-performance Immunoaffinity Chromatography |
| HPIC | High-performance Ion Chromatography |
| HPIEC | High-pressure Ion-exchange Chromatography |
| HPL | Human Placental Lactogen |
| HPLC | High-performance Liquid Chromatography |
| HPLS | Hierarchical Partial Least Squares |
| HPM | Hole-potential Model (in Calcn. Of Mol. Excited States) |
| HPM | Hypervirial-perturbative Method |
| HPMC | Human Peritoneal Mesothelial Cells |
| HPMC | Hydroxypropyl Methylcellulose |
| HPML | High-pressure Mercury Lamp |
| HPMS | Highway Performance Monitoring System |
| HPOTP | High Pressure Oxidizer Turbopump |
| HPPLC | High-performance Precipitation Liquid Chromatography |
| HPPM | Hole-particle Potential Model (in Mol. Excited States Calcns.) |
| HPRT | Hypoxanthine Phosphoribosyltransferase |
| HPS | High Pressure Plasma Spraying |
| HPSAM | H-point Standard Additions Method |
| HPSEC | High Performance Size Exclusion Chromatography |
| HPSN | Hot-pressed Silicon Nitride |
| HPT | High Precision Translator |
| HPTLC | High-Performance Thin-Layer Chromatography |
| HPTP | Human Protein Tyrosine Phosphatase |
| HPTTD | High-performance Thermophilic Two-phase Digestion |
| HPV | Human Papillomavirus |
| HPV | Hypoxic Pulmonary Vasoconstriction |
| HPW | High Pressure Welding |
| HQE | Hemiquantal Equations |
| HQM | Hemiquantal Mechanics (in Mol. Calcns.) |
| HQSAR | Holographic Quantitative Structure-activity Relationship |
| HRA | Health Risk Assessment |
| HRAC | Herbicide Resistance Action Committee |
| HRADS | High Resolution Adsorption |
| HRAP | High Rate Algal Pond |
| HRATS | High-Rate Anaerobic Treatment Systems |
| HRBS | High Resolution Rutherford Backscattering |
| HRC | Rockwell Hardness (C Scale) |
| HRCT | High-Resolution Computed Tomography |
| HRE | Hormone-responsive Element |
| HREE | Heavy Rare Earth Element(s) |
| HREELS | High-resolution Electron Energy-loss Spectroscopy |
| HRELS | High-resolution Electron Energy-loss Spectroscopy |
| HREM | High-resolution Electron Microscopy |
| HRFS | High-resolution Fluorescence Spectroscopy |
| HRGC | High Resolution Gas Chromatography |
| HRGS | High-resolution Gamma-ray Spectrometry |
| HRIBF | Holifield Radioactive Ion Beam Facility |
| HRM | Hydrochlorination Reaction Mixt. |