Buy may refer to a trade, i.e., an exchange of goods and services via bartering or a monetary purchase.
The term may also refer to:
- Buy (inhabited locality), any of several inhabited localities in Russia
- Burlington-Alamance Regional Airport, FAA airport code "BUY"
- Buy (river), a river in Perm Krai and the republics of Bashkortostan and Udmurtia in Russia
- Bunbury Airport, IATA airport code "BUY"
- Buy (album), 1979 album by James Chance and the Contortions
- Buy, slang for believe, find credible, be convinced
- Buy.com, a shopping website founded in 1997; renamed Rakuten.com in 2010