| Acronym | Definition |
|---|
| ISR | Intelligence, Surveillance, and Reconnaissance |
| ISR | Impuesto Sobre la Renta (Spanish: Income Tax; Mexico) |
| ISR | Interrupt Service Routine (assembly programming) |
| ISR | Israel |
| ISR | Institute for Systems Research (University of Maryland) |
| ISR | Institute for Social Research |
| ISR | Institute for Software Research (University of California, Irvine) |
| ISR | International Socialist Review (US leftist journal) |
| ISR | Intersphincteric Resection (cancer) |
| ISR | International Socialist Resistance (youth organization) |
| ISR | Integrated Stress Response |
| ISR | Investissement Socialement Responsable (French: Socially Responsible Investment) |
| ISR | Investigator-Sponsored Research (medical research) |
| ISR | Infant Swimming Resource (Winter Park, FL) |
| ISR | Information Systems Research (MIS journal) |
| ISR | In Situ Recovery (mining process) |
| ISR | Information, Surveillance and Reconnaissance |
| ISR | Instituto de Sistemas e Robotica (University of Coimbra; Portugal) |
| ISR | I Scream Records (est. 1994; Brussels, Belgium) |
| ISR | In Soviet Russia (gaming) |
| ISR | Intersecting Storage Rings (CERN) |
| ISR | Ideal Software Radio |
| ISR | Interrupt Status Register |
| ISR | Instruction Sampling Recording |
| ISR | Integrated Services Router |
| ISR | Interrupt Service Routine |
| ISR | Intermediate Session Routing |
| ISR | In Stent Restenosis |
| ISR | Inverter Spike Resistant (magnet wire insulation) |
| ISR | Inside Sales Representative (HP) |
| ISR | Incoherent Scatter Radar |
| ISR | Immediate Serial Recall (memory) |
| ISR | Induced Systemic Resistance (plant biology) |
| ISR | Instrument Science Report |
| ISR | International Star Registry (est. 1979; Illinois) |
| ISR | International Society of Radiology |
| ISR | Industrial Security Regulation (US DoD 5220.22-R) |
| ISR | Industry Sponsored Research (various organizations) |
| ISR | Information Science Reference (publishing imprint) |
| ISR | Intermediate Session Routing (IBM) |
| ISR | Installation Status Report |
| ISR | International Simple Resale |
| ISR | Income Sensitive Repayment (Federal Family Education Loan Program) |
| ISR | Information Services and Resources |
| ISR | International Survey Research |
| ISR | Institute of Surgical Research (University of Munich, Germany) |
| ISR | International Statistical Review |
| ISR | International Shipping Register (various locations) |
| ISR | Industrial Special Risks |
| ISR | Information Service Representative (various companies) |
| ISR | Individual School Range (head teacher salary scale; UK) |
| ISR | Interactive Student Response |
| ISR | Independent Shifting Rod (Lamborghini transmission) |
| ISR | Insurance Service Representative (various locations) |
| ISR | Incurred Sample Reanalysis |
| ISR | International Student Registration (Long Beach United School District; Long Beach, CA) |
| ISR | Internet Suspend Resume |
| ISR | Injection Site Reaction |
| ISR | Irish Society for Rheumatology (Ireland) |
| ISR | Information Systems Resources |
| ISR | Indie Spinner Rack (talk show) |
| ISR | Institute for Scientific Research, Inc |
| ISR | Institute for Surgical Research (Brooke Army Medical Center, TX, Medical Research Materiel Command, US Army) |
| ISR | Interrupt Service Register |
| ISR | Integrated Switching Regulator (Electronics) |
| ISR | Initial Service Release |
| ISR | Internal Service Request |
| ISR | Individualised Student Record (UK) |
| ISR | Information Storage & Retrieval |
| ISR | Indirect Source Review |
| ISR | Intra Squad Radio |
| ISR | Immediate System Recovery (Raxco) |
| ISR | Implementation Status Report |
| ISR | Integrated Switch Router |
| ISR | In-Service Repair |
| ISR | Inland Slope Rebels (Riverside, CA) |
| ISR | Institute for Safety Research and Reactor Technology |
| ISR | Institute of Snow Research |
| ISR | Irish Sports Report (Notre Dame; Indiana) |
| ISR | In Service Review |
| ISR | Infrared Scanning Radiometer |
| ISR | In School Restriction (punishment) |
| ISR | Independent Science Review |
| ISR | In-Service Recruiter |
| ISR | Integrated SONET Router (Cisco) |
| ISR | Independent Safety Review |
| ISR | Identification Safety Range |
| ISR | Interference Subspace Rejection |
| ISR | Immunostimulator |
| ISR | Intermediate Stress Relief |
| ISR | Interim Systems Review |
| ISR | Inventory/Sales Ratio |
| ISR | Independent Sufficiency Review |
| ISR | Interviewer Severity Rating |
| ISR | Institute of Species Research (India) |
| ISR | Intelligence, Sensors, Reconnaissance |
| ISR | Immediate Spray Reroute |
| ISR | Information Services Request |
| ISR | Input Storage Receiver |
| ISR | Inspection/Surveillance Report |
| ISR | Individual Soldier Radio |
| ISR | Initial Services Requirements (Sprint) |
| ISR | Initial Source Requisition |
| ISR | Instructional System Review |
| ISR | Investment Strategy Review |
| ISR | Integrated Switch Router Technical Specification |
| ISR | Integrated Service Request (Sprint PCS) |
| ISR | Institutional Supporting Research |
| ISR | Information Source Repository |
| ISR | Internal State Reversion |
| ISR | Ingénieur Sûreté Radioprotection (French: Radiation Safety Engineer) |