Ly

LY or ly may refer to:

Government and politics

 * Lý dynasty, a Vietnamese dynasty
 * Labour Youth of Ireland
 * Legislative Yuan, the unicameral legislature of the Republic of China (Taiwan)

Science and technology

 * .ly, the Top-level domain for Libya
 * .ly, the default filetype extension of the GNU LilyPond sheet music format
 * Light-year, the distance that light travels in one year in a vacuum
 * Langley (unit), a unit of energy distribution over a given area

Other uses

 * -ly, an adjectival and adverbial suffix in English
 * Lý (Vietnamese surname), a Vietnamese surname
 * Hungarian ly, or elipszilon, a letter of the Hungarian alphabet
 * Ly the Fairy, a character from Rayman 2: The Great Escape
 * El Al (IATA airline designator LY)
 * Libya (ISO 3166-1 country code LY)