BTW or btw may refer to:
- BTW (company), a Chinese manufacturer
- BTW (conference), a conference series about information technology
- British Traditional Wicca, a set of Wiccan traditions originating in the New Forest region
- Buckfast Tonic Wine, a fortified wine licensed from Buckfast Abbey in Devon
- The Brotherhood of Timber Workers, 1910s labor union
- Burlington Trailways, an Inter-city bus company
- BTW (TV station), in Bunbury, Western Australia
- "B.T.W", a 2021 song by Jay B and Jay Park