BTO
BTO or bto may refer to:
- BTO:
- Brussels Treaty Organisation, also referred to as the Western Union, a European military alliance existing between 1948 and 1954
- Bachman–Turner Overdrive, Canadian rock band
- British Trust for Ornithology
- "Build to order":
- Build to Order as an order-fulfillment strategy
- Build-To-Order (HDB), purchasing arrangement for new Singapore Housing Development Board apartments
- Bismuth titanate (formally BiTiO)
- bto:
- ISO 639-3 code for Rinconada Bikol language