LSI may refer to:

Science and technology

  • Large-scale integration, integrated circuits with tens of thousands of transistors
  • Latent semantic indexing, a technique in natural language processing
  • LSI-11, an early large-scale integration computer processor that implemented the DEC PDP-11 instruction set
  • Langelier saturation index, a measure for water's tendency to form scale
  • Linear shift-invariant systems, the discrete equivalent of linear time-invariant systems

Organizations

  • LSI Corporation, a technology company founded in 1981 as LSI Logic Corporation
  • Lynch Syndrome International, non-profit organisation supporting those affected by Lynch Syndrome
  • Labour and Socialist International, a multinational federation of left wing political parties and trade unions active between 1923 and 1940
  • Socialist Movement for Integration (Lëvizja Socialiste për Integrim), a political party in Albania
  • Lear Siegler Incorporated, a technology company active from 1961 to 2002
  • Lingkaran Survei Indonesia, a survey company in Indonesia

Transportation

  • Lake Superior and Ishpeming Railroad, a railroad service in Michigan, United States
  • Sumburgh Airport (IATA airport code) in Shetland, Scotland

Music

  • "LSI (Love Sex Intelligence)", a single by The Shamen
  • Long-string instrument, a musical instrument

Other uses

  • Landing ship, infantry, a type of troopship or post World War II a landing craft
  • La Salle Institute, a college preparatory school
  • Linguistic Survey of India, a survey of the languages of British India directed by G.A. Grierson
  • Logical Sensory Introvert, a socionics type
  • Lighting & Sound International, a trade magazine