• I-CASE Integrated Computer-Assisted Software Engineering
• I-D Internet Draft
• I/G Individual/Group
• I/O Input/Output
• IAB Internet Architecture Board / Internet Activities Board
• IAC Interpret As Command / Inter-Application Communications
• IAFA Internet Anonymous ftp Archives
• IANA Internet Assigned Numbers Authority
• IANAD I Am Not A Doctor
• IANAL I Am Not A Lawyer
• IAP Internet Access Provider
• IBA Internet Business Association
• IBM International Business Machines
• IC Integrated Circuit
• ICE In-Circuit Emulator
• ICM Independent Color Matching
• ICMP Internet Control Message Protocol
• ICP Internet Control Protocol
• ICW Initialization Command Word
• IDAPI Independent Database Application Programming Interface
• IDE Integrated Drive Electronics / Integrated Development Environment
• IDEA International Data Encryption Algorithm
• IDI Initial Domain Indicator
• IDL Interface Definition Language
• IDMS Integrated Data Management System
• IDP Internetwork Datagram Protocol / Initial Domain Part
• IDT Interrupt Descriptor Table
• IE Interrupt Enable
• IEC International Electrotechnical Commission
• IEEE Institute of Electrical and Electronics Engineers
• IEN Internet Experiment Note
• IESG Internet Engineering Steering Group
• IETF Internet Engineering Task Force
• IFD Image File Directory
• IGES Initial Graphics Exchange Specification
• IGP Interior Gateway Protocol
• IGRP Interior Gateway Routing Protocol
• IGS Internet Go Server
• IINREN Interagency Interim National Research and Education Network
• IMCO In My Considered Opinion
• IMHO In My Humble Opinion
• IMNSHO In My Not-So-Humble Opinion
• IMO In My Opinion
• IMPS Interface Message ProcessorS
• IMR Internet Monthly Report
• IOC Inter-Office Channel
• IOW In Other Words
• IP Instruction Pointer / Internet Protocol
• IPC InterProcess Communication
• IPng Internet Protocol next generation
• IPUMS Integrated Public Use Microdata Series
• IPv6 Internet Protocol version 6
• IPX Internetwork Packet EXchange
• IR Internet Router
• IRC Internet Relay Chat
• IrDA Infrared Data Association
• IREQ Interrupt REQuest
• IRQ Interrupt ReQuest
• IRSG Internet Research Steering Group
• IRTF Internet Research Task Force
• IS Intermediate System
• IS-IS Intermediate System-to-Intermediate System Protocol
• ISA Industry Standard Architecture
• ISDN Integrated Services Digital Network
• ISI Information Sciences Institute
• ISIS Investigative Support Information System
• ISM Industrial Scientific and Medical
• ISO International Standards Organization
• ISO/OSI International Standards Organization/Open System Interconnection model
• ISOC Internet SOCiety
• ISODE International Standards Organization Development Environment
• ISP Internet Service Provider
• ISR Interrupt Service Routine
• ISV Independent Software Vendor
• ITL International Telecommunications Union
• ITT International Telephone and Telegraph
• ITU International Telecommunication Union
• IU Integer Units
• IVHS Intelligent Vehicle Highway System
• IWM Integrated Woz Machine
• IXC IntereXchange Carrier