CLS may refer to:

Academic fields

• Critical legal studies, school of legal philosophy
• Constrained least square statistical estimator
• CLs method to set bounds on particle physics model parameters
• The .cls file extension, used to hold LaTeX manuscripts - see LaTeX § Compatibility and converters

Education

• California Labor School, San Francisco, US 1942–57
• City of London School, UK
• Covington Latin School, Kentucky, US
• Crystal Lake South High School, Illinois, US
• Chicago Law School at The University of Chicago, US
• Columbia Law School at Columbia University, US
• Cornell Law School at Cornell University, US
• Coalition of Latino and Latina Scholars at Teachers College, Columbia University, US
• Critical Language Scholarship Program of the US State Department

Societies and associations

• Caribbean Labour Solidarity, based in London, UK
• Chicago Linguistic Society
• Christian Legal Society
• Communist League of Struggle, US, 1931-1937

Software and technology

• Cable landing station, where a submarine cable comes ashore
• Common Language Specification, Microsoft
• CLS (command) to clear computer screen in several environments
  • CLS (CONFIG.SYS directive), in DR-DOS
• Creative Lighting System, in Nikon speedlights

Medical and science

• Computational Science, an academical research discipline
• Canadian Light Source, a synchrotron light source
• Clinical laboratory science, another name for Medical Technology or Medical Laboratory Science
• Combat lifesaver, US non-medical military role

Music

• City of London Sinfonia
• CLS Music, a record label
• Cali Life Style, a Hip Hop act

Transportation and vehicles

• Capsule launch system for space capsules
• Mercedes-Benz CLS-Class, automobile models

Business and finance

• CLS Group, a global financial market utility
• Celestica, New York Stock Exchange symbol
• CLS Communication, translation services
• CLS Holdings, UK investment company
• Core Labor Standards, ILO