TNI stands for:
- Satna Airport, IATA code TNI
- Tahitian Noni International, Inc.
- Taqramiut Nipingat Inc., an Inuit broadcasting organization in Quebec, Canada
- Telephone Network Interface; see Network Interface Device (NID)
- Tentara Nasional Indonesia (Indonesian); see Military of Indonesia.
- Texas Neuroscience Institute, a research and neurological clinical center
- Thai-Nichi Institute of Technology a private college in Thailand
- Transnational Institute
- Transnationality Index