| I | Current |
| I | Iodine |
| i | Instantaneous current |
| IAP | Imaging Atom Probe |
| IAs | Information Appliances |
| IB | DC Base current |
| IBAE | Ion Beam Assisted Etching |
| IBC | ISDN Burst Controller |
| IBD | Ion Beam Deposition |
| IBE | Ion Beam Etching; Isoelectronic Bound Exciton |
| IBM | International Business machine |
| IBOC | In-Band-On-Channel |
| IC | DC Collector current |
| IC | Integrated Circuit |
| IC | Ion Chromatography |
| ICA | Isotropically Conductive Adhesive |
| ICAM | Integrated CAM |
| ICC | ISDN Communication Controller |
| ICD | Interconnect Diagram |
| ICE | In-Circuit Emulator; Information and Content Exchange Format |
| ICMP | Internet Control Message Protocol |
| ICMS | Integrated Circuit Measurement System |
| ICP | Inductively-Coupled Plasma |
| ICP-AES | Inductively-Coupled Plasma Atomic Emission Spectroscopy |
| ICP-MS | Inductively-Coupled Plasma Mass Spectrometry |
| ICT | Ideal Cycle Time; In-Circuit Test |
| ID | Inside Diameter |
| IDA | Interchange of Data between Administrations |
| IDC | Insulation-Displacement Connection |
| IDDQ | Direct Drain Quiescent Current |
| IDE | Integrated Design Environment |
| IDE | Integrated Device Electronics |
| IDEA | International Data Encryption Standard |
| IDEAlliance | International Digital Enterprise Alliance |
| IDEC | ISDN D-Channel Exchange Controller |
| IDL | Interface Definition Language |
| IDS | Drain-Source Current; Interactive Diagnostic System |
| IDS | Intrusion Detection System |
| IDSS | Saturated Drain-Source Current |
| IEA | Ion Energy Analysis |
| IEC | Infused Emitter Coupling; International Electrotechnical Commission |
| IEC | ISDN Echo Cancellation Circuit; International Engineering Consortium |
| IECQ | International Electronic Component Qualification system |
| IEDF | Ion Energy Distribution Function |
| IEEE | Institute of Electrical and Electronics Engineers |
| IEF | Imaging Energy Filter |
| IEPC | ISDN Enhanced Power Controller |
| IEPS | International Electronics Packaging Society |
| IERN | Internal-External Recurrent Neural network |
| IETF | Internet Engineering Task Force |
| IF | Intermediate frequency |
| IFF | If and only if; Commodore Amiga image format |
| IGBT | Insulated Gate Bipolar Transistor |
| IGES | Integrated Graphics Exchange System |
| IGFET | Insulated-Gate Field-Effect Transistor |
| IGMP | Internet Group Multicast Protocol |
| IHPC | ISDN High-Voltage Power Controller |
| IHT | Ideal Handler Time |
| iHTML | inline HTML |
| IIC | Intra Integrated circuit |
| IIOP | Internet Inter-ORB Protocol |
| IIP3 | Input 3rd order Intercept Point |
| IIT | Indian Institute of Technology |
| IL | Insertion Loss |
| ILB | Inner Lead Bond |
| ILD | InterLevel Dielectric; InterLayer Dielectric |
| ILM | Integrated Laser Modulator; Instrumental Landing System |
| ILS | Intracavity Laser Spectroscopy |
| IM | Integrated Model; InterModulation; Instant Messaging |
| IM4DTTV | Integrated Modem for DTTV |
| IMAP | Internet Mail Access Protocol |
| IMD | InterMetal Dielectric; InterModulation Distortion |
| IMP | InterModulation Product |
| IMPATT | IMPact Avalanche and Transit Time |
| IMR | Integrated Model Repository; InterModulation Ratio |
| IMS | Ion Mobility Spectroscopy; Intelligent Manufacturing System |
| IMT | International Mobile Telecommunications |
| INCAMS | Individual cassette manufacturing system |
| INSAT | Indian National Satellite |
| INTELSAT | International Telecommunication Satellite |
| IOT | Inductive Output Amplifier |
| IP | Intellectual Property |
| IP | Internet Protocol |
| IP3 | 3rd order Intercept Point |
| IPAT | ISDN Primary-Rate Access Transceiver |
| IPC | Institute for interconnecting and Packaging ICs |
| IPC | International Press Telecommunications Council |
| IPDC | Internet Protocol Data Casting |
| IPM | Inches Per Minute |
| IPO | Initial Public Offering |
| IPR | Intellectual Property Rights |
| IPRM | Indium Phosphide Related Materials |
| IPS | Intrusion Prevention System |
| IPT | Ideal Process Time |
| IPTC | International Press and Telecommunications Council |
| IR | Infra-Red |
| IRAS | Infrared Reflection-Absorption Spectroscopy |
| IRD | Integrated Receiver Decoder |
| IRFPA | IR Focal Plane Array |
| IRIS | Imaging of Radicals Interacting with Surfaces |
| IRM | Image Reject Mixer; Isothermal Remnant Magnetization |
| IRN | Internal Recurrent Neural network |
| IRONMAN | Improving Reliability Of New Machines At Night |
| IRPC | ISDN Remote Power Controller |
| IRS | InfraRed Spectroscopy |
| IRTC-1 | Interconnect Reliability Test Chip-1 |
| IS | Information Systems; Interface Specifications; Integrated Systems |
| ISA | Instrumentation Society of America |
| ISAC | ISDN Subscriber Access Controller |
| ISAN | International Standard Audiovisual Number |
| ISBN | International Standard Book Number |
| ISC | Industry Steering Council; Inter System Crossing |
| ISC | Integrated Security Concept |
| ISCAN | International Smart Card Associations network |
| ISD | Interface State Density |
| ISDB | Integrated Services Digital Broadcasting |
| ISDN | Integrated Services Digital network |
| ISE | Integrated Solid Effect |
| ISEM | Inspection/review Specific Equipment Model |
| ISFET | Ion Selective Field Effect Transistor |
| ISHM | International Society for Hybrid Microelectronics |
| ISM | Industrial Scientific and Medical |
| ISMA | Internet Streaming Media Alliance |
| ISO | International Standards Organization |
| ISP | Interface Strain Parameter |
| ISP | Internet Service Provider |
| ISRO | Indian Space Research Organization |
| ISS | Ion Scattering Spectrometry/Spectroscopy |
| ISV | Individual Source Vias |
| IT | Information & Technology |
| ITAC | ISDN Terminal Adapter Circuit |
| ITD | Isothermal Desorption Spectrometry |
| ITRI | Interconnection Technology Research Institute |
| ITT | Inter-Test Time |
| ITU | International Telecommunication Union |
| ITV | Interactive Television |
| IVP | Integrated Vacuum Processing |
| IVR | Interactive Voice Response |
| IWOC | Internet Way Of Computing |
| IWRS | Isolated Word Recognition System |
| I/O | Input/output |
| I2L | Integrated injector logic |
| I300I | International 300 mm Initiative |
| Ie | Total emitter current |
| Ieff | Effective current |
| If | Interface |
| Imax | Maximum current |
| IMG | GEM Paint image format |
| Imin | Minimum current |
| In | Indium |
| InAs | Indium Arsenide |
| InGaAs | Indium Gallium Arsenide |
| InGaAsP | Indium Gallium Arsenide Phosphide |
| InSb | Indium Antimonide |
| I-PAL | Improved PAL |
| Is | Secondary current |
| It | Total current |
| iTV | Interactive Tele Vision |
