| Acronym | Definition |
|---|
| IS | Information System(s) |
| IS | In Service |
| IS | Internet Service |
| IS | Information Services |
| IS | International System (of units) |
| IS | International Standard |
| IS | Industry Standard |
| IS | Image Size (semiconductor manufacturing) |
| IS | Information Security |
| IS | International Staff (NATO) |
| IS | Island |
| IS | Image Studio |
| IS | Internet Solutions (South Africa) |
| IS | Internet Society |
| IS | Indian Standards |
| IS | Israel (Including Israel-Jordan & Israel-Syria Demilitarized Zones) |
| IS | Industrial Safety |
| IS | Industrial Society |
| IS | Industrial Security |
| IS | Instruction Set |
| IS | Information Structure (linguistics) |
| IS | Income Support (UK) |
| IS | Internal Stop |
| IS | Internal Security |
| IS | Internal Standard |
| IS | Installation Survey |
| IS | Initial Study |
| IS | Industry Sector |
| IS | Integrated System |
| IS | Integrated Science |
| IS | Irish Standard (fire alarms) |
| IS | Integrated Schedule |
| IS | Industrial Specialist |
| IS | Intelligent Services Gateway |
| IS | Intelligence Specialist (Navy Rating) |
| IS | Intelligent Systems (IEEE International Conference) |
| IS | Intelligent Sport (Lexus model) |
| IS | Infrastructure Service |
| IS | International Supplement (ODT) |
| IS | Iceland |
| IS | Indianapolis Star (newspaper) |
| IS | Intermediate School |
| IS | Intermediate System |
| IS | Iron Soldier (Atari Jaguar game) |
| IS | Insertion Sequence (molecular biology) |
| IS | Interface Specification |
| IS | Internal Specification |
| IS | Intelligent Sensor |
| IS | Investigations Service (OPM) |
| IS | Inner Sphere (Mech Warrior) |
| IS | Interstate System |
| IS | Importance Sampling |
| IS | Interim Status |
| IS | Interim Standard (series of communication standards) |
| IS | Islamic State |
| IS | Instrumentation System |
| IS | Imagery Server |
| IS | Integer Sort |
| IS | Interrupt Status |
| IS | Intelligence Squadron |
| IS | Installshield |
| IS | Initial Spares |
| IS | Imperial Stout |
| IS | Indexed Sequential |
| IS | Information Superiority |
| IS | Image Stabilization (camera feature) |
| IS | Inspection Services |
| IS | Image Shack (image hosting service) |
| IS | Intrinsic Safety |
| IS | International Standardization |
| IS | Image Stabilizer (camera lens) |
| IS | Information Separator |
| IS | Induction Soldering |
| IS | Isles of Scilly (UK) |
| IS | Infinite Stratos (Japanese novel series) |
| IS | Iasi (Romania) |
| IS | International Socialists |
| IS | Indentation Strength |
| IS | Intrinsically Safe |
| IS | Inbred Strain |
| IS | Interscope Records (record label) |
| IS | Isotope Separation |
| IS | Ipecac Syrup |
| IS | Ilta-Sanomat (Finnish newspaper) |
| IS | Impôt sur les Sociétés (French: corporation tax) |
| IS | Immunosuppression (treatment complication) |
| IS | Iron Savior (band) |
| IS | Ismailia (Egyptian automobile license plate) |
| IS | Infrasound |
| IS | Induced Sputum |
| IS | Infraspinatus (muscle) |
| IS | Isernia, Molise (Italian province) |
| IS | Intercostal Space |
| IS | Incentive Spirometer |
| IS | Investigation Scientist (US NASA) |
| IS | Inventory of Systems |
| IS | Indicating Switch |
| IS | Interferon Sensitivity |
| IS | Isotopic Source |
| IS | Instituti I Statistikes (Albanian: Statistics Institute) |
| IS | Internal Silencer |
| IS | Infinite Spawn (gaming) |
| IS | Instituto Sertão (Brasil) |
| IS | Imtiazi Sanad (Certificate of Distinction Pakistan Armed Forces) |
| IS | Immaculata Symphony (Immaculata, PA) |
| IS | Itakura-Saito distortion |
| IS | Investments Equal Savings (macroeconomic curve) |
| IS | Insurgent Sisterhood (Star Wars Galaxies guild) |
| IS | Industry Solutions Module |
| IS | Immersible Switch |
| IS | (USN Rating) Intelligence Specialist |
| IS | Interactive Structures, Incorporated |