| Acronym | Definition |
|---|
| SIG | Special Interest Group |
| SIG | Signal |
| SIG | Signature |
| SIG | Signor (Italian: Mister; used like Mr.) |
| SIG | Système d'Information Géographique (French) |
| SIG | Summer Institute for the Gifted |
| SIG | Sistema de Información Geográfica (Spanish) |
| SIG | Susquehanna International Group (Bala Cynwyd, Pennsylvania) |
| SIG | School Improvement Grant (US Department of Education) |
| SIG | Services Industriels de Genève (Switzerland) |
| SIG | Software Installation Guide (instructions) |
| SIG | Southern Indiana Gas and Electric Company |
| SIG | Sigmoidoscopy |
| SIG | Solomon Islands Government |
| SIG | Signalman |
| SIG | Service d'Information du Gouvernement (French: Department of Government Information) |
| SIG | Signature File |
| SIG | Support and Information Group |
| SIG | Settings File |
| SIG | Signaller |
| SIG | Special Investigation Group (various locations) |
| SIG | Sigmoidoscope |
| SIG | Structural Informatics Group (Washington) |
| SIG | Standardized Information Gathering (questionnaire) |
| SIG | Spectrum Is Green (from the TV Series, Captain Scarlet) |
| SIG | Strategy Implementation Group (various organizations) |
| SIG | Secure Internet Gateway |
| SIG | Social Issues Group (Malaysia) |
| SIG | Surface Immunoglobulins |
| SIG | SMDS Interest Group |
| SIG | Strategic Initiatives Group (USMC) |
| SIG | State Innovation Grant (US EPA) |
| SIG | Senior Integration Group (US DoD) |
| SIG | Senior Interdepartmental Group |
| SIG | Stamford Industrial Group (Stamford, CT) |
| SIG | Signature Investigations Group (Michigan) |
| SIG | Small Inducible Gene (inflammatory response) |
| SIG | Softgoal Interdependency Graph |
| SIG | Stress in General (scale) |
| SIG | Street Index Guide |
| SIG | Single Instant Game |
| SIG | System Integration Group |
| SIG | Strategic Intelligence Group |
| SIG | Shanghai International Group Corporation Limited |
| SIG | Schweizerische Industrie Gesellschaft AG |
| SIG | Selective Integral Ground |
| SIG | Site Integration Group |
| SIG | Self Inspection Guide |
| SIG | Ship Improvement Guide |
| SIG | PMW Poster Type File (Printmaster Premier 8.0 file extension) |
| SIG | Specific Industry Group |
| SIG | Staff Involvement Group (UK NHS) |
| SIG | Strategic Integration Group |
| SIG | Shanghai Industries Group, Ltd. (Shanghai, China) |
| SIG | Service Instruction Guidance (University of Miami high school tutoring program) |
| SIG | SSDS Interface Gateway |
| SIG | Service Integration Gateway |