| Acronym | Definition |
|---|
| SIGA | Saskatchewan Indian Gaming Authority |
| SIGA | Secure Internet Gateway Appliance |
| SIGA | Sistemas Integrales de Gestión Ambiental (Spanish: Integrated Environmental Management Systems; various locations) |
| SIGA | Sistema Integrado Guatemalteco de Autobuses (Spanish: Integrated Guatemalan Bus System) |
| SIGA | Simplified Improved Gaussian Approximation |
| SIGA | Special Interest Group in Andrology (ESHRE) |
| SIGA | Semaine Internationale de la Gentillesse et de l'Altruisme (International Week of Kindness and Altruism) |
| SIGA | Silizium, Galvanik Und Abformung |
| SIGA | Sunshine in Government Act of 1976 |
| SIGA | School Improvement Grant Administrator (Georgia) |