Stanisław Lem (1921-2006), Polish science fiction author.

Lunar Excursion Module, a former name of the Apollo Lunar Module.

Curtis Lemansky, one of the major characters on the television series The Shield.

The Law of excluded middle, a law in logics or rhetorics.

Lunar Efficient Missionary, a fictional space ship in Stanisław Lem's Peace on Earth novel.

Lem, author of the webcomic Bunny.

LEM is a brand name of Generalmusic.

Learnable Evolution Model, an evolutionary computation method that employs machine learning to guide evolution process.

Liquid Elastomer Molding (LEM), a unique gasket technology developed by Federal-Mogul Corporation.

Leyton Midland Road railway station, England; National Rail station code LEM