Sigma (disambiguation)

Sigma may refer to:
* Sigma (Σ, σ, or ς), of the Greek alphabet

Companies:
* Sigma TV a television channel in Cyprus
* Sigma Company, an Australian company. Its main operations include Pharmaceuticals and Pharmacies
* Sigma Corporation, a Japanese camera and lens manufacturer
* Sigma Company Limited, a Hungarian debt management company
* Sigma Designs, Inc., a US semiconductor manufacturer
* SIGMA (verification service), Nielsen Media Research's tracking system for videos
* SIGMA (insurance), an Albanian insurance company
* Sigma-Aldrich Corporation
* Sigma Sport, a German manufacturer of electronic sports equipment

In science:
* Summation operator forming a series in mathematics Σ
* Standard deviation in statistics σ
* Divisor function in number theory σ
* Sigma-algebra (σ-algebra, σ-field) in set theory
* A busy beaver function in computability theory Σ
* Stefan-Boltzmann constant of radiation in physics σ
* Sigma factor of RNA polymerase in biology σ
* Sigma (chemistry), the electronic substituent constant of molecules in physical chemistry σ
* Sigma baryon, a class of baryons in particle physics
* Pauli matrices in quantum physics
* Cross section
* Sigma bond in chemistry σ
* Sigma receptor, a subtype of opioid receptor
* Sigma (meteorology), a ratio of pressure in the atmosphere.In geography:
* Sigma, Capiz, a municipality in the Philippines

In economics:
* SIGMA (Economic Model), a practical macroeconomic model developed by the Federal Reserve's International Finance Department

In popular culture:

* Mitsubishi Sigma, motor car, a variant of the Galant
* GM Sigma platform, a mid-size car automobile platform from General Motors Corporation
* Six Sigma, a quality management program
* Smith & Wesson Sigma, a Smith & Wesson firearm
* Sigma (Mega Man X), villain in the Mega Man X video game series
* Ninja Gaiden Sigma, a PlayStation 3 title in the "Ninja Gaiden" video game series
* [http://www.discogs.com/artist/Sigma+(8) Sigma] , a drum and bass artist, most famous for his 2007 tune 'all blue'.