Log may refer to:
- Chip log, a device used in navigation to estimate the speed of a vessel through water.
- Data log, a record of sequential data
- Laplacian of Gaussian
- Log (journal), an architectural magazine
- Log (village), a former urban-type settlement in Volgograd Oblast, Russia; since 2007—a village (selo)
- Logarithm, the mathematical operation that is the inverse of exponentiation, or the result of this operation.
- Logbook, a log of important events in the management, operation and navigation of a ship
- Web log, Web's log, Weblog, 'blog, or blog, a reverse chronological journal
- Wooden log, also known as timber, wood from trees used for construction or wood pulp for paper production
- The Log (guitar), a nickname given to Les Paul's first solid body electric guitar built in the 1930s