1K or 1-K may refer to:
- Astra 1K satellite
- Astra 1KR satellite
- 1K ZX Chess computer program
- Southern Cross Distribution (IATA code)
- Sutra (air company) (IATA code)
- BMP-1K, see BMP-1
- BRM-1K, see BMP-1 variants
- HH-1K, see Bell UH-1 Iroquois variants
- XMODEM-1K, a model of XMODEM
- YMODEM-1K, a model of YMODEM
- GSXR 1K, or Suzuki GSX-R1000
- Typ 1K, a chassis code of Volkswagen Golf Mk5
- SSH 1K (WA), see Washington State Route 509
- Premier 1K, a membership level of United Airlines MileagePlus program
- 1k as one thousand