Langmuir may refer to:
- Langmuir (crater), an impact crater on the Moon's far side
- Langmuir (journal), an academic journal on colloids, surfaces and interfaces, published by the American Chemical Society
- Langmuir (unit), a unit of exposure of an adsorbate/gas to a substrate used in surface science to study adsorption
- Langmuir Cove, a cove in the north end of Arrowsmith Peninsula, Graham Land, Antarctica
People:
- Alexander Langmuir (1910–1993), an American epidemiologist
- Charles Langmuir, a geologist and nephew of Irving Langmuir
- Gavin I. Langmuir (1924–2005), a Canadian veteran of World War II, an historian of anti-Semitism and a medievalist at Stanford University
- Irving Langmuir (1881–1957), an American Nobel Prize-winning chemist and physicist known for:
- Irving Langmuir House
- Langmuir circulation, a wind-driven ocean circulation
- Langmuir equation, an equation that relates the coverage or adsorption of molecules on a solid surface to gas pressure or concentration of a medium above the solid surface at a fixed temperature
- Langmuir probe
- Langmuir wave, a rapid oscillation of the electron density in conducting media such as plasmas or metals