LAC may refer to:

• Los Angeles County in California
• La Crescenta, California, unincorporated area in Los Angeles County
• California State Prison, Los Angeles County
• Line of Actual Control, effective border between India and China
• Latin America and the Caribbean, United Nations geoscheme region
• Longburn Adventist College, Christian school in Longburn, New Zealand

Lac is the scarlet resinous secretion of a number of species of lac insects, of which the most commonly cultivated species is Kerria lacca.

Laç (; ) is a town and a former municipality in Lezhë County, northwestern Albania. At the 2015 local government reform it became a subdivision and the seat of the municipality Kurbin. It was the administrative center of the former Kurbin District. The population at the 2011 census was 17,086. Its associated football (soccer) club is KF Laçi.

The  suffix -lock in Modern English survives only in . It descends from Old English -lác which was more productive, carrying a meaning of "action or proceeding, state of being, practice, ritual". As a noun, Old English lác means "play, sport", deriving from an earlier meaning of "sacrificial ritual or hymn" (Proto-Germanic *laikaz). A putative term for a "hymn to the gods" (*ansu-laikaz) in early Germanic paganism is attested only as a personal name, Oslac.