The abbreviation LM or lm may refer to:

• Legg Mason, a U.S. investment management firm; NYSE ticker symbol
• Livingston Energy Flight, an Italian airline; IATA airline designator code
• Lockheed Martin, a U.S. defense contractor
• London Midland, a rail operator based in the West Midlands, England

• IS/LM model in macroeconomics, where LM refers to Liquidity preference-Money supply
• Lean manufacturing
• Maltese lira, the former currency of Malta

• Lagrange multiplier, a method for finding maxima and minima subject to constraints
• Language model, mathematical model used in language processing and speech recognition
• Lebesgue measure
• Leonard-Merritt mass estimator
• Levenberg–Marquardt algorithm
• Lumen, unit of luminous flux

• Legion of Merit, a United States military decoration

• 24 Hours of Le Mans race, and related car models
• Late model, a class of Racing car
• Left midfielder, a defensive position in association football

• Liberal Movement, a defunct Australian political party

• Living Marxism magazine, published under the name LM between 1997 and 2000
• LM (magazine), a defunct British computer game magazine

• Apollo Lunar Module spacecraft
• LAN Manager, a Microsoft network operating system
• LM hash, a Microsoft password hash function
• Light meter
• Light microscope
• Line maintenance, a type of Aircraft maintenance checks
• Linear Monolithic, a National Semiconductor prefix for their linear integrated circuits (e.g. LM317) referring to the monolithic IC, where the entire circuit is constructed in a single piece of silicon (LM-series list)
• Long mode, a CPU mode of operation where 64-bit programs are executed (lm is also set as a CPU flag)

• Lourenço Marques, Pearl of the Indian Ocean, Mozambique
• Lower Mainland, a region in British Columbia, Canada
• Le Mans, a place in France.

• Limburg-Weilburg, Germany
• Liptovský Mikuláš, Slovakia
• County Leitrim, Ireland

• L&M, a brand of cigarettes
• Lower Merion High School, a Pennsylvania secondary school
• Little Mix, a British four-piece girl group

• IM (disambiguation)